As filed with the Securities and Exchange Commission on January 10, 2001

                        Registration No. 333-____________


                       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 (I.R.S. Employer Identification No.)
                        of incorporation or organization)

                             224 South 108th Avenue
                              Omaha, Nebraska 68154
               (Address of principal executive offices) (Zip Code)

      MessagingDirect Ltd. Amended and Restated Employee Share 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)

<TABLE>
<CAPTION>
                         CALCULATION OF REGISTRATION FEE

================================== ========================== ==================== =================== ==============
<S>                                <C>                        <C>                   <C>                <C>
                                                                Proposed Maximum       Proposed          Amount of
    Title of Securities to be       Amount to be Registered    Offering Price Per       Maximum         Registration
           Registered                         (1)                    Share             Aggregate           Fee (2)
                                                                                    Offering Price (2)
================================== ========================== ==================== =================== ==============
      Class A Common Stock,              370,000 shares              $0.01               $3,700              $1
        $0.005 par value
</TABLE>

(1)  Pursuant  to  Rule  416,  this  registration   statement  also  covers  any
additional  shares of Class A Common  Stock  which may be offered or issued as a
result of stock splits, stock dividends or similar transactions.

(2)  Pursuant to Rule  457(h),  computed on the basis of the  exercise  price of
the  outstanding  options  granted under the  MessagingDirect  Ltd.  Amended and
Restated  Employee  Share  Option  Plan  and  assumed  by  Transaction   Systems
Architects,  Inc.  The  exercise  price of the  outstanding  options  assumed by
Transaction Systems Architects, Inc. is $0.01 per share.


                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Certain Documents by Reference

         Transaction   Systems   Architects,   Inc.  (the   "Company"))   hereby
incorporates by reference in this  Registration  Statement the documents  listed
in (a) through  (b) below  previously  filed with the  Securities  and  Exchange
Commission  (the  "Commission")  under the  Securities  Exchange Act of 1934, as
amended (the "Exchange Act"):

            (a)   The Company's Annual  Report on Form 10-K for the  fiscal
                  year ended  September  30, 2000.

            (b)   The   description  of  the Company's  Class  A  Common
                  Stock  contained  in  the Company's registration  statement
                  on Form  8-A  that the Company  filed  on January 11, 1995,
                  including  any amendment or reports  that we file for the
                  purposes of updating  this description.

         All  documents  subsequently  filed with the  Commission by the Company
pursuant to Sections  13(a),  13(c),  14 and 15(d) of the  Exchange Act prior to
the filing of a  post-effective  amendment  which  indicates that all securities
offered  hereby  have  been  sold  or  which  deregisters  all  securities  then
remaining  unsold shall be deemed to be incorporated  herein by reference and to
be a part hereof from the dates of filing of such documents.


Item 6.  Indemnification of Directors and Officers.

         Section 145 of the Delaware  General  Corporation  Law provides for the
indemnification  of  officers  and  directors,  subject to certain  limitations.
The  Certificate  of  Incorporation  of the  registrant  expressly  provides for
indemnification  of an  officer or  director  made a party or  threatened  to be
made a party to  proceedings  by  reason of the fact  that  such  person  was an
officer or director.  The  Certificate  of  Incorporation  also  authorizes  the
registrant  to maintain  officer and director  liability  insurance,  and such a
policy is currently in effect.


Item 8.  Exhibits

     Exhibit
     Number
    --------

        5         Opinion of Baker & McKenzie
       23         Consent of Arthur Andersen LLP
       24         Power of Attorney (included in Signature Page)


Item 9.  Undertakings.

         (a)      The undersigned registrant 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 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 information  required to be included in a post-effective  amendment
by those  paragraphs is contained in periodic  reports  filed by the  registrant
pursuant  to  Section  13  or  Section  15(d)  of  the  Exchange  Act  that  are
incorporated by reference in this registration statement.

              2.       That, for the purpose of determining any liability  under
the 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  post-effective
amendment  any of the  securities  being  registered  which remain unsold at the
termination of the offering.

         (b)      The  undersigned   registrant   hereby  undertakes  that,  for
purposes  of  determining  any  liability  under  the Act,  each  filing  of the
registrant'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
Act may be  permitted to  directors,  officers  and  controlling  persons of the
registrant pursuant to the foregoing  provisions,  or otherwise,  the registrant
has been advised that in the opinion of the Securities  and Exchange  Commission
such  indemnification  is against  public policy as expressed in the Act and is,
therefore,  unenforceable.  In  the  event  that  a  claim  for  indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred  or  paid  by  a  director,  officer,  or  controlling  person  of  the
registrant  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 registrant will, unless in the opinion of
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 Act and will be  governed by
the final adjudication of such issue.
<PAGE>
                                   SIGNATURES
         The  Registrant.  Pursuant to the  requirements  of the  Securities Act
of 1933,  the registrant  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 this 10th day of January, 2001.

                                     TRANSACTION SYSTEMS ARCHITECTS, INC.

                                     By: /s/ William E. Fisher
                                     -------------------------------------
                                             William E. Fisher, Chairman, Chief
                                             Executive Officer and Director


                                POWER OF ATTORNEY

         We, the  undersigned  officers  and  directors of  Transaction  Systems
Architects,  Inc.,  hereby  severally and  individually  constitute  and appoint
William E. Fisher,  Dwight G. Hanson and David P. Stokes,  and each of them, the
true and  lawful  attorneys  and  agents of each of us to  execute  in the name,
place and stead of each of us  (individually  and in any capacity  stated below)
any and all  amendments  to this  Registration  Statement  on Form S-8,  and all
instruments  necessary  or advisable in  connection  therewith,  and to file the
same with the  Securities  and Exchange  Commission,  each of said attorneys and
agents to have  power to act with or  without  the other and to have full  power
and  authority  to do and  perform  in the  name  and on  behalf  of each of the
undersigned  every  act  whatsoever  necessary  or  advisable  to be done in the
premises  as fully and to all intents  and  purposes  as any of the  undersigned
might or could do in person,  and we hereby  ratify and confirm  our  signatures
as they may be signed by our said  attorneys  and agents and each of them to any
and all such amendments and other instruments.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the date indicated.


/s/ William E. Fisher          Chairman, Chief Executive        January 10, 2001
--------------------------     Officer and Director
William E. Fisher

/s/ Dwight G. Hanson           Chief Financial Officer          January 10, 2001
--------------------------     and Senior Vice President
Dwight G. Hanson

/s/ Edward C. Fuxa             Controller                       January 10, 2001
--------------------------
Edward C. Fuxa

/s/ Charles E. Noell, III      Director                         January 10, 2001
--------------------------
Charles E. Noell, III

/s/ Jim D. Kever               Director                         January 10, 2001
--------------------------
Jim D. Kever

/s/ Larry G. Fendley           Director                         January 10, 2001
--------------------------
Larry G. Fendley

/s/ Roger K. Alexander         Director                         January 10, 2001
--------------------------
Roger K. Alexander

/s/ Gregory J. Duman           Director                         January 10, 2001
--------------------------
Gregory J. Duman
<PAGE>
                                  EXHIBIT INDEX

Exhibit Number        Description

         5            Opinion of Baker & McKenzie
         23           Consent of Arthur Andersen LLP
         24           Power of Attorney (included in Signature Page)
[{"type": "S-8", "sequence": "1", "filename": "0001.txt", "description": "REGISTRATION STATEMENT", "secsgml_size_bytes": 13437}]
{"company-data": {"conformed-name": "TRANSACTION SYSTEMS ARCHITECTS INC", "cik": "0000935036", "assigned-sic": "7372", "irs-number": "470772104", "state-of-incorporation": "DE", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-53504", "film-number": "1506664"}, "business-address": {"street1": "224 SOUTH 108TH AVE", "city": "OMAHA", "state": "NE", "zip": "68154", "phone": "4023907600"}, "mail-address": {"street1": "224 SOUTH 108TH", "city": "OMAHA", "state": "NE", "zip": "68154"}}
As filed with the Securities and Exchange Commission on January 10, 2001

                        Registration No. 333-____________

                       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 (I.R.S. Employer Identification No.)
                        of incorporation or organization)

                             224 South 108th Avenue
                              Omaha, Nebraska 68154
               (Address of principal executive offices) (Zip Code)

      MessagingDirect Ltd. Amended and Restated Employee Share 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)
CALCULATION OF REGISTRATION FEE

================================== ========================== ==================== =================== ==============
Proposed Maximum       Proposed          Amount of
    Title of Securities to be       Amount to be Registered    Offering Price Per       Maximum         Registration
           Registered                         (1)                    Share             Aggregate           Fee (2)
                                                                                    Offering Price (2)
================================== ========================== ==================== =================== ==============
      Class A Common Stock,              370,000 shares              $0.01               $3,700              $1
        $0.005 par value
(1)  Pursuant  to  Rule  416,  this  registration   statement  also  covers  any
additional  shares of Class A Common  Stock  which may be offered or issued as a
result of stock splits, stock dividends or similar transactions.

(2)  Pursuant to Rule  457(h),  computed on the basis of the  exercise  price of
the  outstanding  options  granted under the  MessagingDirect  Ltd.  Amended and
Restated  Employee  Share  Option  Plan  and  assumed  by  Transaction   Systems
Architects,  Inc.  The  exercise  price of the  outstanding  options  assumed by
Transaction Systems Architects, Inc. is $0.01 per share.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Certain Documents by Reference

         Transaction   Systems   Architects,   Inc.  (the   "Company"))   hereby
incorporates by reference in this  Registration  Statement the documents  listed
in (a) through  (b) below  previously  filed with the  Securities  and  Exchange
Commission  (the  "Commission")  under the  Securities  Exchange Act of 1934, as
amended (the "Exchange Act"):

            (a)   The Company's Annual  Report on Form 10-K for the  fiscal
                  year ended  September  30, 2000.

            (b)   The   description  of  the Company's  Class  A  Common
                  Stock  contained  in  the Company's registration  statement
                  on Form  8-A  that the Company  filed  on January 11, 1995,
                  including  any amendment or reports  that we file for the
                  purposes of updating  this description.

         All  documents  subsequently  filed with the  Commission by the Company
pursuant to Sections  13(a),  13(c),  14 and 15(d) of the  Exchange Act prior to
the filing of a  post-effective  amendment  which  indicates that all securities
offered  hereby  have  been  sold  or  which  deregisters  all  securities  then
remaining  unsold shall be deemed to be incorporated  herein by reference and to
be a part hereof from the dates of filing of such documents.

Item 6.  Indemnification of Directors and Officers.

         Section 145 of the Delaware  General  Corporation  Law provides for the
indemnification  of  officers  and  directors,  subject to certain  limitations.
The  Certificate  of  Incorporation  of the  registrant  expressly  provides for
indemnification  of an  officer or  director  made a party or  threatened  to be
made a party to  proceedings  by  reason of the fact  that  such  person  was an
officer or director.  The  Certificate  of  Incorporation  also  authorizes  the
registrant  to maintain  officer and director  liability  insurance,  and such a
policy is currently in effect.

Item 8.  Exhibits

     Exhibit
     Number
    --------

        5         Opinion of Baker & McKenzie
       23         Consent of Arthur Andersen LLP
       24         Power of Attorney (included in Signature Page)

Item 9.  Undertakings.

         (a)      The undersigned registrant 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 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 information  required to be included in a post-effective  amendment
by those  paragraphs is contained in periodic  reports  filed by the  registrant
pursuant  to  Section  13  or  Section  15(d)  of  the  Exchange  Act  that  are
incorporated by reference in this registration statement.

              2.       That, for the purpose of determining any liability  under
the 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  post-effective
amendment  any of the  securities  being  registered  which remain unsold at the
termination of the offering.

         (b)      The  undersigned   registrant   hereby  undertakes  that,  for
purposes  of  determining  any  liability  under  the Act,  each  filing  of the
registrant'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
Act may be  permitted to  directors,  officers  and  controlling  persons of the
registrant pursuant to the foregoing  provisions,  or otherwise,  the registrant
has been advised that in the opinion of the Securities  and Exchange  Commission
such  indemnification  is against  public policy as expressed in the Act and is,
therefore,  unenforceable.  In  the  event  that  a  claim  for  indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred  or  paid  by  a  director,  officer,  or  controlling  person  of  the
registrant  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 registrant will, unless in the opinion of
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 Act and will be  governed by
the final adjudication of such issue.
SIGNATURES
         The  Registrant.  Pursuant to the  requirements  of the  Securities Act
of 1933,  the registrant  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 this 10th day of January, 2001.

                                     TRANSACTION SYSTEMS ARCHITECTS, INC.

                                     By: /s/ William E. Fisher
                                     -------------------------------------
                                             William E. Fisher, Chairman, Chief
                                             Executive Officer and Director

                                POWER OF ATTORNEY

         We, the  undersigned  officers  and  directors of  Transaction  Systems
Architects,  Inc.,  hereby  severally and  individually  constitute  and appoint
William E. Fisher,  Dwight G. Hanson and David P. Stokes,  and each of them, the
true and  lawful  attorneys  and  agents of each of us to  execute  in the name,
place and stead of each of us  (individually  and in any capacity  stated below)
any and all  amendments  to this  Registration  Statement  on Form S-8,  and all
instruments  necessary  or advisable in  connection  therewith,  and to file the
same with the  Securities  and Exchange  Commission,  each of said attorneys and
agents to have  power to act with or  without  the other and to have full  power
and  authority  to do and  perform  in the  name  and on  behalf  of each of the
undersigned  every  act  whatsoever  necessary  or  advisable  to be done in the
premises  as fully and to all intents  and  purposes  as any of the  undersigned
might or could do in person,  and we hereby  ratify and confirm  our  signatures
as they may be signed by our said  attorneys  and agents and each of them to any
and all such amendments and other instruments.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the date indicated.

/s/ William E. Fisher          Chairman, Chief Executive        January 10, 2001
--------------------------     Officer and Director
William E. Fisher

/s/ Dwight G. Hanson           Chief Financial Officer          January 10, 2001
--------------------------     and Senior Vice President
Dwight G. Hanson

/s/ Edward C. Fuxa             Controller                       January 10, 2001
--------------------------
Edward C. Fuxa

/s/ Charles E. Noell, III      Director                         January 10, 2001
--------------------------
Charles E. Noell, III

/s/ Jim D. Kever               Director                         January 10, 2001
--------------------------
Jim D. Kever

/s/ Larry G. Fendley           Director                         January 10, 2001
--------------------------
Larry G. Fendley

/s/ Roger K. Alexander         Director                         January 10, 2001
--------------------------
Roger K. Alexander

/s/ Gregory J. Duman           Director                         January 10, 2001
--------------------------
Gregory J. Duman
EXHIBIT INDEX

Exhibit Number        Description

         5            Opinion of Baker & McKenzie
         23           Consent of Arthur Andersen LLP
         24           Power of Attorney (included in Signature Page)