8-K

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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT


     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934


                        Date of Report: December 13, 2004
                        (Date of earliest event reported)

                            -------------------------


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


          Delaware                   0-25346                     47-0772104
(State or other jurisdiction       (Commission                (I.R.S. Employer
      of incorporation)            File Number)              Identification No.)


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


                                 (402) 334-5101
              (Registrant's telephone number, including area code)

                            -------------------------


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

                 __ Written communications pursuant to Rule 425
                   under the Securities Act (17 CFR 230.425)

                 __ Soliciting material pursuant to Rule 14a-12
                   under the Exchange Act (17 CFR 240.14a-12)

          __ Pre-commencement communications pursuant to Rule 14d-2(b)
                  under the Exchange Act (17 CFR 240.14d-2(b))

          __ Pre-commencement communications pursuant to Rule 13e-4(c)
                  under the Exchange Act (17 CFR 240.13e-4(c))


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 Item 7.01.  Regulation FD Disclosure.

     On December 13, 2004, Transaction Systems Architects, Inc. issued a press
release announcing that its Board of Directors has approved a stock repurchase
program authorizing the Company to acquire up to $80 million of its Class A
Common Stock. A copy of this press release is attached hereto as Exhibit 99.1
and is being furnished, not filed, under Item 7.01 of Form 8-K.









                                    SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                        TRANSACTION SYSTEMS ARCHITECTS, INC.


 Date: December 13, 2004                By:        /s/ Dennis P. Byrnes
                                           -----------------------------------
                                                     Dennis P. Byrnes
                                                  Senior Vice President,
                                              General Counsel and Secretary








                                  EXHIBIT INDEX

       Exhibit
       Number     Description

         99.1     Press Release, dated December 13, 2004.

EX-99

                                                                    Exhibit 99.1

                                                                    News Release

TRANSACTION SYSTEMS ARCHITECTS INC
224 SOUTH 108 AVENUE
OMAHA, NEBRASKA 68154
402.334.5101
FAX 402.390.8077



For more information contact:
William J. Hoelting
Vice President, Investor Relations
402.390.8990

FOR IMMEDIATE RELEASE


        Transaction Systems Architects Announces Stock Repurchase Program

(OMAHA, Neb.--December 13, 2004)--Transaction Systems Architects, Inc.
(Nasdaq:TSAI) today announced that its Board of Directors has approved a stock
repurchase program authorizing the Company to acquire up to $80 million of its
Class A Common Stock. Purchases will be made from time to time as market and
business conditions warrant, in open market, negotiated or block transactions,
in accordance with applicable laws, rules and regulations. Transaction Systems
Architects, Inc. has approximately 37.8 million shares of Class A Common Stock
outstanding.

"Given the Company's strong balance sheet and cash flow, the stock repurchase
program represents an excellent use of capital and reflects our commitment to
enhancing stockholder value," said Gregory D. Derkacht, President and CEO.


About Transaction Systems Architects, Inc.

The Company's software facilitates electronic payments by providing consumers
and companies access to their money. Its products are used to process
transactions involving credit cards, debit cards, secure electronic commerce,
mobile commerce, smart cards, secure electronic document delivery and payment,
checks, high-value money transfers, bulk payment clearing and settlement, and
enterprise e-infrastructure. The Company's solutions are used on more than 1,700
product systems in 76 countries on six continents.


Forward-Looking Statements

         Statements included in this press release may contain forward-looking
statements. Such forward-looking statements are made pursuant to the safe-harbor
provisions of the Private Securities Litigation Reform Act of 1995. The
forward-looking statements in this press release are subject to a variety of
risks and uncertainties. Actual results could differ materially.

         For a detailed discussion of these and other risk factors, interested
parties should review the Company's filings with the Securities and Exchange
Commission, including the Company's Form 10-K filed on December 23, 2003, the
Company's Form 10-Q filed on February 17, 2004, the Company's form 10-Q filed on
May 17, 2004, and the Company's Form 10-Q filed on August 11, 2004.