As filed with the Securities and Exchange Commission on May 10, 2002.

                                           Registration No. 333-________________

________________________________________________________________________________



                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    FORM S-8


             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                              --------------------

                      TRANSACTION SYSTEMS ARCHITECTS, INC.
              (Exact name of registrant as specified in its charter)

           Delaware                                              47-0772104
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

                             224 South 108th Avenue
                              Omaha, Nebraska 68154
          (Address of principal executive offices, including zip code)

                      Transaction Systems Architects, Inc.
                  2002 Non-Employee Director Stock Option Plan
                            (Full title of the plan)

                              David P. Stokes, Esq.
                          General Counsel and Secretary
                      Transaction Systems Architects, Inc.
                             224 South 108th Avenue
                              Omaha, Nebraska 68514
                                 (402) 334-5101
 (Name, address and telephone number, including area code, of agent for service)
                              --------------------

                                 with a copy to:

                             Albert G. McGrath, Jr.
                                Baker & McKenzie
                            2300 Trammell Crow Center
                                2001 Ross Avenue
                               Dallas, Texas 75201





                         CALCULATION OF REGISTRATION FEE
                                                                                    
====================================== ================ =================== ==================== ===================
                                                         Proposed maximum    Proposed maximum
                                        Amount to be      offering price    aggregate offering       Amount of
Title of securities to be registered   registered (1)     per share (2)          price (2)        registration fee
- -------------------------------------- ---------------- ------------------- -------------------- -------------------
Class A Common Stock, par value            250,000            $10.795           $2,698,750            $248.28
$.005 per share
====================================== ================ =================== ==================== ===================

(1)  Pursuant to Rule 416 promulgated under the Securities Act of 1933, as
     amended (the "Securities Act"), there are also being registered such
     additional shares of Class A Common Stock of Transaction Systems
     Architects, Inc. (the "Company"), par value $.005 per share (the "Common
     Stock"), as may become issuable pursuant to the anti-dilution provisions of
     the Transaction Systems Architects, Inc. 2002 Non-Employee Director Stock
     Option Plan (the "2002 Stock Option Plan").
(2)  Estimated solely for the purpose of calculating the registration fee
     pursuant to Rule 457(c) and (h) promulgated under the Securities Act and is
     based upon the average of the high and low sale prices of the Common Stock
     on February 26, 2002, as reported on the National Association of Securities
     Dealers Automated Quotations system.



PART I INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS Item 1. Plan Information Not filed with this registration statement (this "Registration Statement"). Item 2. Registrant Information and Employee Plan Annual Information Not filed with this Registration Statement. PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT Item 3. Incorporation of Documents by Reference The Company hereby incorporates by reference in this Registration Statement the documents listed in (a) through (c) below, which it has previously filed with the Securities and Exchange Commission (the "Commission") under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). All documents subsequently filed by the Company pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, prior to the filing of a post-effective amendment to this Registration Statement that indicates that all shares of Common Stock offered hereunder have been sold or that deregisters all shares of Common Stock then remaining unsold, shall be deemed to be incorporated herein by reference and to be a part hereof from the date of filing of such documents. (a) The Company's Quarterly Report on Form 10-Q for the quarter ended December 31, 2001, filed with the Commission on February 12, 2002. (b) The Company's Annual Report on Form 10-K for the fiscal year ended September 30, 2001, filed with the Commission on December 27, 2001. (c) The description of the Company's Class A Common Stock contained in the Company's Registration Statement on Form 8-A (File No. 000-25346), filed with the Commission on January 9, 1995, including any amendments or reports that the Company files for the purpose of updating this description. Item 4. Description of Securities Not Applicable. Item 5. Interest of Named Experts and Counsel Not Applicable. Item 6. Indemnification of Directors and Officers Pursuant to Section 145 of the General Corporation Law of the State of Delaware (the "Delaware Code"), the Company generally has the power to indemnify its present and former directors, officers, employees and agents against expenses, judgments, fines and amounts paid in settlement incurred by them in connection with any suit (other than a suit by or in the right of the Company) to which they are, or are threatened to be made, a party by reason of their serving in such positions, or by reason of their serving at the Company's request in such positions for another corporation, partnership, joint venture, trust or other enterprise, so long as they acted in good faith and in a manner they reasonably believed to be in, or not opposed to, the best interests of the Company, and with respect to any criminal action, they had no reasonable cause to believe their conduct was unlawful. Section 145 of the Delaware Code further provides that in connection with the defense or settlement of any action by or in the right of the corporation, a Delaware corporation may indemnify its present and former directors, officers, employees and agents against expenses actually and reasonably incurred by them if, in connection with the matters in issue, they acted in good faith, in a manner they reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification may be made with respect to any claim, issue or matter as to which such person has been adjudged liable to the corporation unless the Court of Chancery or the court in which such action or suit was brought approves such indemnification. The statute also expressly provides that the power to indemnify authorized thereby is not exclusive of any rights granted under any bylaw, agreement, vote of stockholders or disinterested directors, or otherwise. As permitted by the Delaware Code, the Amended and Restated Certificate of Incorporation, as amended, of the Company (the "Certificate of Incorporation") provides for the indemnification of directors and officers, subject to certain limitations. The Certificate of Incorporation expressly provides for the indemnification of a director or officer made a party, or threatened to be made a party, to any proceeding by reason of the fact that he or she is a director or officer of the Company. Pursuant to the Certificate of Incorporation, the Company has the power to purchase and maintain insurance for its present and former directors, officers, employees and agents. Such a policy is currently in effect. The above discussion of the Certificate of Incorporation and of Section 145 of the Delaware Code is not intended to be exhaustive and is qualified in its entirety by such Certificate of Incorporation and the Delaware Code. The Amended and Restated Bylaws, as amended, of the Company (the "Bylaws") provide that the Company shall indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the Company) by reason of the fact that he is or was or has agreed to become a director, officer, employee or agent of the Company, or is or was serving or has agreed to serve at the request of the Company as a director, officer, employee or agent of another constituent corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against costs, charges, expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by him or on his behalf in connection with such action, suit or proceeding and any appeal therefrom, if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the Company, and, with respect to any criminal action or proceeding, had no reasonable cause to believe his conduct was unlawful. The termination of any action, suit or proceeding by judgment, order, settlement, conviction, or upon a plea of nolo contendere or its equivalent shall not, of itself, create a presumption that the person did not meet the standards of conduct set forth above. The Company shall indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the Company to procure a judgment in its favor by reason of the fact that he is or was or has agreed to become a director, officer, employee or agent of the Company, or is or was serving or has agreed to serve at the request of the Company as a director, officer, employee or agent of another constituent corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against costs, charges and expenses (including attorneys' fees) actually and reasonably incurred by him or on his behalf in connection with the defense or settlement of such action or suit and any appeal therefrom, if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the Company, except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable for gross negligence or wanton misconduct in the performance of his duty to the Company unless and only to the extent that the Court of Chancery of Delaware or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of such liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such costs, charges and expenses which the Court of Chancery or such other court shall deem proper. To the extent that a director, officer, employee or agent of the Company has been successful on the merits or otherwise, including, without limitation, the dismissal of an action without prejudice, in defense of any action, suit or proceeding referred described herein, or in the defense of any claim, issue or matter therein, he shall be indemnified against all costs, charges and expenses (including attorneys' fees) actually and reasonably incurred by him or on his behalf. Item 7. Exemption from Registration Claimed Not Applicable. Item 8. Exhibits The following are filed as exhibits to this Registration Statement: Exhibit Description No. 4.1(1) Transaction Systems Architects, Inc. 2002 Non-Employee Director Stock Option Plan 4.2(2) Form of Common Stock Certificate 4.3(2) Amended and Restated Certificate of Incorporation of the Company, and amendments thereto 4.4(3) Amended and Restated Bylaws of the Company, and first amendment thereto 5.1(1) Opinion of Baker & McKenzie 23.1(1) Consent of Arthur Andersen LLP 23.2(1) Consent of Baker & McKenzie (included in Exhibit 5.1) 24.1(1) Power of Attorney (included on the signature page of this Registration Statement) - ---------------- (1) Filed herewith. (2) Incorporated by reference to Exhibit 3.01 of the Company's Registration Statement (File No. 33-88292) on Form S-1. (3) Incorporated by reference to Exhibit 3.02 of the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 1999. Item 9. Undertakings (a) The undersigned Company hereby undertakes: (1) To file, during any period in which offers or sales are being made, a post-effective amendment to this Registration Statement: (i) To include any prospectus required by Section 10(a)(3) of the Securities Act; (ii) To reflect in the prospectus any facts or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective Registration Statement; (iii) To include any material information with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such information in the Registration Statement; provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the Registration Statement is on Form S-3 or Form S-8, and the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the Commission by the Company pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the Registration Statement. (2) That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. (3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering. (b) The undersigned Company hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the Company's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. (c) Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the Company pursuant to the foregoing provisions, or otherwise, the Company has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Company of expenses incurred or paid by a director, officer or controlling person of the Company in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Company will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

SIGNATURES Pursuant to the requirements of the Securities Act, the Company certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Omaha, State of Nebraska, on February 27, 2002. TRANSACTION SYSTEMS ARCHITECTS, INC. By: /s/ DWIGHT G. HANSON -------------------------------------- Dwight G. Hanson, Chief Financial Officer, Treasurer and Senior Vice President POWER OF ATTORNEY Each person whose signature appears below hereby constitutes and appoints Dwight G. Hanson his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution for him and his name, place and stead, in any and all capacities, to sign any or all amendments (including pre- or post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Commission, and hereby grants to such attorney-in-fact and agent, full power and authority to do and perform each and every act and thing requisite and necessary to be done, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorney-in-fact and agent, or his substitute, may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the date indicated. Signature Title Date /s/ GREGORY D. DERKACHT President, Chief Executive Officer and February 27, 2002 - ----------------------------------- Director Gregory D. Derkacht /s/ GREGORY J. DUMAN Chairman of the Board and Director February 27, 2002 - ----------------------------------- Gregory J. Duman /S/ LARRY G. FENDLEY Interim Chief Operating Officer and Director February 27, 2002 - ----------------------------------- Larry G. Fendley /s/ DWIGHT G. HANSON Chief Financial Officer, Treasurer and February 27, 2002 - ----------------------------------- Senior Vice President Dwight G. Hanson /s/ EDWARD C. FUXA Chief Accounting Officer, Vice President February 27, 2002 - ----------------------------------- and Controller Edward C. Fuxa /s/ JIM D. KEVER Director February 27, 2002 - ----------------------------------- Jim D. Kever /s/ ROGER K. ALEXANDER Director February 27, 2002 - ----------------------------------- Roger K. Alexander

EXHIBIT INDEX Exhibit Description No. 4.1(1) Transaction Systems Architects, Inc. 2002 Non-Employee Director Stock Option Plan 4.2(2) Form of Common Stock Certificate 4.3(2) Amended and Restated Certificate of Incorporation of the Company, and amendments thereto 4.4(3) Amended and Restated Bylaws of the Company, and first amendment thereto 5.1(1) Opinion of Baker & McKenzie 23.1(1) Consent of Arthur Andersen LLP 23.2(1) Consent of Baker & McKenzie (included in Exhibit 5.1) 24.1(1) Power of Attorney (included on the signature page of this Registration Statement) - ---------------- (1) Filed herewith. (2) Incorporated by reference to Exhibit 3.01 of the Company's Registration Statement (File No. 33-88292) on Form S-1. (3) Incorporated by reference to Exhibit 3.02 of the Company's Annual Report on Form 10-K for the fiscal year ended September 30, 1999.

                                                                     EXHIBIT 4.1

                      TRANSACTION SYSTEMS ARCHITECTS, INC.
                  2002 NON-EMPLOYEE DIRECTOR STOCK OPTION PLAN

        1.  Approval of the Plan.  Subject to approval of the Transaction
Systems Architects, Inc. 2002 Non-Employee Director Stock Option Plan by
the stockholders of the Company at the next Annual Meeting of Stockholders
(presently scheduled to take place on February 19, 2002), the Board approved
the Plan in January 2002.

        2. Purpose of the Plan.  The purpose of the Transaction Systems
Architects, Inc. 2002 Non-Employee Director Stock Option Plan is to promote the
long-term growth of the Company by increasing the proprietary interest of
Non-Employee Directors in the Company and to retain highly qualified and capable
Non-Employee Directors.

        3.    Definitions.  Unless the context clearly indicates otherwise, the
following terms shall have the following meanings:

            "Board" shall mean the Board of Directors of the Company.

            "Code" shall mean the Internal Revenue Code of 1986, as amended.

            "Company" shall mean Transaction Systems Architects, Inc.

            "Disability" shall mean permanent and total disability as defined in
Section 22(e)(3) of the Code.

            "Duman" and "Alexander" shall mean Mr. Gregory J. Duman and Roger K.
Alexander, respectively, each presently a nominee for election to the Board as a
Non-Employee Director.

            "Employee" shall mean an employee of either the Company or any
subsidiary thereof.

            "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended.

            "Fair Market Value" shall mean the closing bid price on the date in
question, as such price is reported by the National Association of Securities
Dealers on the NASDAQ National Market or any successor system for a share of
Class A Common Stock of the Company.

            "Option" shall mean an option to purchase Shares granted under this
Plan.

            "First Option Grant Date" shall mean March 4, 2002.

            "Optionee" shall mean a Non-Employee Director of the Company to whom
an Option has been granted under this Plan.

            "Non-Employee Director" shall mean a director of the Company who is
not an employee of the Company or any subsidiary of the Company at the time any
option is granted hereunder. For so long as an individual continues to serve
without interruption as either a Non-Employee Director or an Employee subsequent
to his/her receipt of an option hereunder, said person shall for purposes of
those options previously granted hereunder continue to be considered a
Non-Employee Director.

            "Plan" shall mean the Transaction Systems Architects, Inc. 2002
Non-Employee Director Stock Option Plan, as amended from time to time.

            "Shares" shall mean shares of the Class A Common Stock of the
Company.

            "Stock Option Agreement" shall mean a written agreement between a
Non-Employee Director and the Company evidencing an Option in such form as the
Board shall approve.

        4. Administration of the Plan. The Plan shall be administered by the
Board. The Board shall be authorized to interpret the Plan and may, from time to
time, adopt, amend and rescind such rules, regulations and procedures as it may
deem advisable to implement and administer the Plan. The interpretation and
construction by the Board of any provision of the Plan, any Option granted
hereunder or any agreement evidencing any such Option shall be final, conclusive
and binding upon all parties.

        All expenses and liabilities incurred by the Board in the administration
of the Plan shall be borne by the Company. The Board may employ attorneys,
consultants, accountants or other persons in connection with the administration
of the Plan. The Company, and its officers and directors, shall be entitled to
rely upon the advice, opinions or valuations of any such persons. No member of
the Board shall be liable for any action, determination or interpretation taken
or made in good faith with respect to the Plan or any Option granted hereunder.

        The Board shall have full power and authority to interpret and construe
the Plan and adopt such rules and regulations as it shall deem necessary and
advisable to implement and administer the Plan. All such interpretations, rules
and regulations shall be conclusive and binding on all parties.

        5. Life of Option Grants.  Notwithstanding and term or conditions to the
contrary stated herein, no Option granted under the Plan shall be exercisable,
in whole or in part, after 10 years from the date of grant.

        6. Specific Option Grants. Provided and to the extent that each of them
is duly elected at the next Annual Meeting of Stockholders (presently scheduled
to be held on February 19, 2002) to serve as a member of the Board, on the First
Option Grant Date the following grants of Options shall be made:

            (i)  Duman shall be granted an Option to purchase 20,000 Shares; and

            (ii) Alexander shall be granted an Option to purchase 16,000 Shares.

        7. Other Option Grants. Beginning on the day after the next Annual
Meeting of Stockholders (presently scheduled to be held on February 19, 2002),
any individual who is for the first time either duly appointed by the Board or
elected by the Stockholders as a Non-Employee Director shall on the date of
either such appointment or election be granted an Option to purchase 20,000
Shares. Beginning with the Annual Meeting of Stockholders to be held in 2003,
each Non-Employee Director who is a duly elected member of the Board upon the
conclusion of that or any subsequent Annual Meeting of Stockholders and who has
previously served as a Non-Employee Director shall be granted an Option to
purchase 4,000 shares on the date of such Annual Meeting of Stockholders.

        8. Option Agreement. Each Option granted under the Plan shall be
evidenced by a Stock Option Agreement. No person shall have any rights under any
Option granted under the Plan unless and until the Company and the person to
whom such Option shall have been granted shall have executed and delivered a
written Option Agreement. Exclusive of the Exercise Price, date of grant, and
the time of exercise, the terms and conditions of each Option Agreement shall be
determined by the Board.

        9. Shares Subject to the Plan. Subject to adjustment as provided in
Section 14, the aggregate number of Shares which may be issued or delivered upon
the exercise of Options shall not exceed 250,000 Shares. The Shares that may be
subject to Options may be either authorized and unissued shares or shares
reacquired at any time and now or hereafter held as treasury stock, as the Board
may determine.

        10. Non-Transferability of Options. Options shall not be transferable
otherwise than by will or the laws of descent and distribution, and during an
Optionee's lifetime an Option shall be exercisable only by the Optionee.

        11. Non-Qualified Options. Each Option issued hereunder shall not
constitute nor be treated as an "incentive stock option" as defined in Section
422 of the Code or an option described in Section 423(b) of the Code: each
Option will be a "non-qualified stock option" for federal income tax purposes.

        12.  Exercise Price.  The Option exercise price per share under each
Option shall be equal to 100% of the Fair Market Value per Share subject to the
Option on the Option Grant Date.

        13. Exercise of Options. An Option may not be exercised during the first
year after the Option Grant Date. After the first anniversary of the Option
Grant Date, it may be exercised as to not more than 331/3% of the Shares
available for purchase under the Option and, after each of the second and third
anniversaries of the Option Grant Date, it may be exercised as to not more than
an additional 331/3% of such shares plus any shares as to which the Option might
theretofore have been exercisable but shall not have been exercised. No option
shall be exercised later than ten years after the Option Grant Date.

        Except as provided in this Section 13, all Options granted to a
Non-Employee Director shall automatically be forfeited by such person at the
time such person shall cease to be a Non-Employee Director, provided, however
that an Optionee may exercise then-vested options within 30 days after
termination unless said termination of results from an act of (a) fraud or
intentional misrepresentation or (b) embezzlement, misappropriation or
conversion of assets or opportunities of the Company or any direct or indirect
majority-owned subsidiary of the Company, by such Non-Employee Director. The
determination of whether termination resulted from such act shall be made by the
Board, whose determination shall be conclusive. If service by the Optionee as a
Non-Employee Director terminates by reason of Disability, the unexercised
portion of any Option held by such Optionee at that time may be exercised within
one year after the date on which the Optionee ceased to serve as a Non-Employee
Director, but no later than the date the Option expires, and to the extent that
the Optionee could have otherwise exercised such Option if it had been
completely exercisable. To the extent that the Optionee is not entitled to
exercise the Option on such date, or if the Optionee does not exercise it within
the time specified, such Option shall terminate. The Board shall have the
authority to determine the date an Optionee ceases to serve as a Non-Employee
Director by reason of his Disability. If an Optionee dies while serving as a
Non-Employee Director of the Company (or dies within a period of 30 days after
termination of his service as a Non-Employee Director for any reason other than
Disability or within a period of one year after termination of his service as a
Non-Employee Director by reason of Disability), the unexercised portion of any
Option held by such Optionee at the time of his death may be exercised within
one year after the date of such Optionee's death, but no later than the date the
Option expires, and to the extent that the Optionee could have otherwise
exercised such Option if it had been completely exercisable. Such Option may be
exercised by the executor or administrator of the Optionee's estate or by any
person or persons who shall have acquired the Option directly from the Optionee
by bequest or inheritance. To the extent that the Option is not entitled to be
exercised on such date or if the Option is not exercised within the time
specified, such Option shall terminate.

        An Option may not be exercised for a fraction of a Share. An Option
shall be deemed to be exercised when written notice of such exercise has been
given to the Company in accordance with the terms of the Stock Option Agreement
by the Optionee entitled to exercise the Option and full payment for the Shares
with respect to which the Option is exercised has been received by the Company.
Payment for the Shares upon exercise of an Option shall be made in cash, by
certified check, or by any other method of payment that may be permitted under
applicable law and authorized by the Board. Each exercise of an Option shall
reduce, by an equal number, the total number of Shares that may thereafter be
purchased under such Option.

        14. Adjustments. In the event that the outstanding Shares shall be
increased or decreased or changed into or exchanged for a different number or
kind of shares of stock or other securities of the Company or of another
corporation, effected without the receipt of consideration by the Company,
through reorganization, merger or consolidation, recapitalization,
reclassification, stock split, reverse stock split, split-up, combination or
exchange of shares or declaration of any dividends payable in Shares, the Board
shall appropriately adjust, subject to any required action by the stockholders
of the Company, (i) the number of Shares (and the Option exercise price per
share) subject to the unexercised portion of any outstanding Option (to the
nearest possible full share), and (ii) the number of Shares for which Options
may be granted under the Plan, as set forth in Section 9 hereof, and such
adjustments shall be final, conclusive and binding for all purposes of the Plan.
Except as expressly provided herein, no issuance by the Company of shares of
stock of any class shall affect, and no adjustment by reason thereof shall be
made with respect to, the number or price of Shares subject to an Option.

        Notwithstanding the foregoing, in the event of (i) any offer or proposal
to holders of the Company's Shares relating to the acquisition of their Shares,
including, without limitation, through purchase, merger or otherwise, or (ii)
any transaction generally relating to the acquisition of substantially all of
the assets or business of the Company, or (iii) the dissolution or liquidation
of the Company, the Board may make such adjustment as it deems equitable in
respect of outstanding Options (and in respect of the Shares for which Options
may be granted under the Plan), including, without limitation, the revision,
acceleration, cancellation, or termination of any outstanding Options, or the
change, conversion or exchange of the Shares under outstanding Options (and of
the Shares for which Options may be granted under the Plan) into or for
securities or other property of another corporation. Any such adjustments by the
Board shall be final, conclusive and binding for all purposes of the Plan.

        15. Amendment of the Plan. The Board may amend the Plan from time to
time as it deems desirable in its sole discretion without approval of the
stockholders of the Company, except to the extent stockholder approval is
required by Rule 16b-3 of the Exchange Act, applicable NASDAQ National Market or
stock exchange rules, applicable Code provisions, or other applicable laws or
regulations.

        16. Termination of the Plan. The Board may terminate the Plan at any
time in its sole discretion. No Option may be granted hereunder after
termination of the Plan. The termination or amendment of the Plan shall not
alter or impair any rights or obligations under any Option previously granted
under the Plan in any material adverse way without the affected Optionee's
consent.

        17. Modification, Extension and Renewal of Options. Within the
limitations of the Plan and subject to Section 11, the Board may modify, extend
or renew outstanding Options or accept the cancellation of outstanding Options
for the granting of new Options in substitution therefor. Notwithstanding the
preceding sentence, except for any adjustment described in Section 14, (i) no
modification of an Option shall, without the consent of the Optionee, alter or
impair any rights or obligations under any Option previously granted under the
Plan in any material adverse way without the affected Optionee's consent, and
(ii) the exercise price of outstanding Options may not be altered, amended or
modified.

        18.  Governing Law.  The Plan and all Stock Option Agreements executed
in connection with the Plan shall be governed by and construed in accordance
with the laws of the State of Delaware, without regard to conflict of laws
principles.

        19.  Successors.  This Plan is binding on and will inure to the benefit
of any successor to the Company, whether by way of merger, consolidation,
purchase, or otherwise.

        20. Severability. If any provision of the Plan or any Stock Option
Agreement shall be held illegal or invalid for any reason, such illegality or
invalidity shall not affect the remaining provisions of the Plan or Stock Option
Agreement, and the Plan and each Stock Option Agreement shall each be construed
and enforced as if the invalid provisions had never been set forth therein.

        21. Plan Provisions Control. The terms of the Plan govern all Options
granted under the Plan, and in no event will the Board have the power to grant
any Option under the Plan that is contrary to any of the provisions of the Plan.
In the event any provision of any Option granted under the Plan shall conflict
with any term in the Plan, the term in the Plan shall control.

        22.  Headings.  The  headings used in the Plan are for convenience only,
do not constitute a part of the Plan, and shall not be deemed to limit,
characterize, or affect in any way any provisions of the Plan, and all
provisions of the Plan shall be construed as if no captions had been used in the
Plan.

        23. Rights as Stockholder. No person shall have any right as a
stockholder of the Company with respect to any Shares which are subject to an
Option unless and until such person becomes a stockholder of record with respect
to such Shares.



                                                                     EXHIBIT 5.1
                                BAKER & MCKENZIE
                                Attorneys at Law

                            2300 Trammell Crow Center
                                2001 Ross Avenue
                               Dallas, Texas 75201


                                February 27, 2002


Board of Directors
Transaction Systems Architects, Inc.
224 South 108th Avenue
Omaha, Nebraska 68154

Re:  Transaction Systems Architects, Inc. (the "Company")

Gentlemen:

         The Company has filed with the Securities and Exchange Commission (the
"Commission") a registration statement (the "Registration Statement") on Form
S-8 under the Securities Act of 1933, as amended (the "Act"). The Registration
Statement covers (a) 250,000 shares of Class A Common Stock, par value $.005 per
share, of the Company (the "Common Stock"), which shares shall be issued
pursuant to the Transaction Systems Architects, Inc. 2002 Non-Employee Stock
Option Plan (the "2002 Stock Option Plan"), and (b) such additional shares of
Common Stock as may become issuable pursuant to the anti-dilution provisions of
the 2002 Stock Option Plan (such shares collectively referred to as the
"Securities").

         We have acted as counsel to the Company in connection with the
preparation and filing of the Registration Statement. In rendering this opinion
we have examined such corporate records, documents and instruments of the
Company and such certificates of public officials, have received such
representations from officers of the Company, and have reviewed such questions
of law as in our judgment are necessary, relevant or appropriate to enable us to
render the opinion expressed below. In such examination, we have assumed the
genuineness of all signatures, the authenticity of all corporate records,
documents and instruments submitted to us as originals, the conformity to
original documents of all documents submitted to us as conformed, certified or
photostatic copies thereof, and the authenticity of the originals of such
conformed, certified or photostatic copies.

         Based upon such examination and review and upon representations made to
us by officers of the Company, we are of the opinion that upon issuance and
delivery of the Securities in accordance with the applicable terms and
conditions of the 2002 Stock Option Plan and upon receipt by the Company of the
full consideration for the Securities as determined pursuant to the 2002 Stock
Option Plan, the Securities will be legally issued, fully paid and
nonassessable.

         This firm consents to the filing of this opinion as an exhibit to the
Registration Statement. In giving such consent, we do not admit that we come
within the category of persons whose consent is required by Section 7 of the Act
or the rules and regulations of the Commission thereunder.

                                                Very truly yours,



                                                Baker & McKenzie



                                                                    EXHIBIT 23.1

Consent of independent public accountants


As independent public accountants, we hereby consent to the incorporation by
reference in this Registration Statement on Form S-8 of our report dated October
26, 2001, included in Transaction Systems Architects, Inc.'s Annual Report on
Form 10-K for the fiscal year ended September 30, 2001, and to all references to
our firm included in this Registration Statement.

Arthur Andersen LLP

Omaha, Nebraska,
February 27, 2002