Exhibit 4.2

                       FIRST AMENDMENT TO CREDIT AGREEMENT


     THIS FIRST  AMENDMENT TO CREDIT  AGREEMENT (the  "Amendment"),  dated as of
March 14, 1997,  is entered into by and between SPSS INC. (the  "Borrower")  and
BANK OF AMERICA ILLINOIS (the "Bank").


                                    RECITALS

     A. The Borrower and the Bank are parties to a Credit  Agreement dated as of
March 15, 1996 (the "Credit Agreement")  pursuant to which the Bank has extended
certain credit  facilities to the Borrower and certain of its  Subsidiaries,  on
and subject to the terms and conditions set forth therein.

     B. The Borrower has requested that the Bank agree to certain  amendments of
the Credit Agreement.

     C. The Bank is willing to amend the Credit Agreement,  subject to the terms
and conditions of this Amendment.

     NOW,  THEREFORE,  for valuable  consideration,  the receipt and adequacy of
which are hereby acknowledged, the parties hereto hereby agree as follows:

     1. Defined Terms.  Unless otherwise defined herein,  capitalized terms used
herein  shall  have  the  meanings,  if any,  assigned  to  them  in the  Credit
Agreement.

         2.  Amendments to Credit Agreement.

     (a) Section  1.01 of the Credit  Agreement  shall be amended at the defined
term  "Availability  Period" by amending and restating  such defined term in its
entirety as follows:

                           "'Availability Period':  the period commencing on
                           the date of this Agreement and ending on the date
                           that is the earlier to occur of (a) March 13,
                           1998, and (b) the date on which the Bank's
                           commitment to extend credit hereunder terminates."

     (b) The first clause of subsection 2.02(b) of the Credit Agreement shall be
amended in its entirety to read as follows:

                                    (b) In lieu of the interest  rate  described
                           above, the Borrower may elect during the Availability
                           Period to have all or portions of Advances  under the
                           Revolving Facility bear interest at the Offshore Rate
                           plus 1.00% per annum during an Offshore Rate Interest
                           Period, subject to the following requirements:









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     (c) Section 2.04 of the Credit  Agreement  shall be amended in its entirety
to read as follows:

                                    2.04  Commitment Fee. The Borrower shall pay
                           to the Bank a commitment fee at the rate of 0.25% per
                           annum on the  average  daily  unused  portion  of the
                           credit provided under this Agreement.  The commitment
                           fee shall be computed on a calendar quarter basis and
                           shall be payable  on the last day of each  successive
                           calendar   quarter   and  on  the  last  day  of  the
                           Availability Period.

     (d) Section 7.10 of the Credit  Agreement  shall be amended in its entirety
to read as follows:

                                    7.10 Quick  Ratio.  The  Borrower  shall not
                           permit, as of the last day of any fiscal quarter,  on
                           a  consolidated  basis,  the  ratio of its (a) sum of
                           cash,   short-term   cash   investments,   marketable
                           securities  not  classified as long-term  investments
                           and accounts  receivable to (b) current  liabilities,
                           to be less than 0.90:1.00.

     (e) Section 7.11 of the Credit  Agreement  shall be amended in its entirety
to read as follows:

                                    7.11 Tangible Net Worth.  The Borrower shall
                           not permit, as of the last day of any fiscal quarter,
                           on a consolidated basis, its Tangible Net Worth to be
                           less than 90% of the amount of Tangible  Net Worth as
                           of September 30, 1996, plus the sum of (i) 75% of net
                           income  after  income  taxes   (without   subtracting
                           losses)  earned in each quarterly  accounting  period
                           commencing after September 30, 1996, and (ii) 100% of
                           the net proceeds  from any equity  securities  issued
                           after September 30, 1996.

     (f) Section 7.12 of the Credit  Agreement  shall be amended in its entirety
to read as follows:

                                    7.12  Total   Liabilities  to  Tangible  Net
                           Worth. The Borrower shall not permit,  as of the last
                           day of any fiscal quarter,  on a consolidated  basis,
                           the  ratio  of  its  (a)  total  liabilities,  to (b)
                           Tangible Net Worth to be greater than 2.00:1.00.

     3.  Representations  and  Warranties.  The Borrower  hereby  represents and
warrants to the Bank as follows:









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     (a) No Default or Event of Default has occurred and is continuing.

     (b)  The  execution,  delivery  and  performance  by the  Borrower  of this
Amendment have been duly authorized by all necessary  corporate and other action
and do not and will not require any registration  with,  consent or approval of,
notice to or action by, any person  (including  any  governmental  authority) in
order to be effective and  enforceable.  The Credit Agreement as amended by this
Amendment  constitutes the legal, valid and binding obligations of the Borrower,
enforceable against it in accordance with its respective terms, without defense,
counterclaim or offset.

     (c) All  representations  and  warranties of the Borrower  contained in the
Credit Agreement are true and correct.

     (d) The  Borrower is entering  into this  Amendment on the basis of its own
investigation  and for its own reasons,  without  reliance  upon the Bank or any
other person.

     4. Effective  Date.  This  Amendment  will become  effective as of the date
first above written (the "Effective Date"),  provided that each of the following
conditions precedent is satisfied:

                  (a) The Bank has received  from the  Borrower a duly  executed
original  (or,  if  elected by the Bank,  an  executed  facsimile  copy) of this
Amendment.

                  (b) The  Bank  has  received  from  the  Borrower  a copy of a
resolution  passed by the board of directors of such  corporation,  certified by
the  Secretary or an Assistant  Secretary of such  corporation  as being in full
force and effect on the date hereof,  authorizing  the  execution,  delivery and
performance of this Amendment.

         5. Reservation of Rights. The Borrower acknowledges and agrees that the
execution  and  delivery  by the Bank of this  Amendment  shall not be deemed to
create a course of dealing or otherwise  obligate the Bank to forbear or execute
similar amendments under the same or similar circumstances in the future.

         6.       Miscellaneous.

                  (a) Except as herein expressly amended,  all terms,  covenants
and  provisions  of the Credit  Agreement are and shall remain in full force and
effect and all  references  therein to such Credit  Agreement  shall  henceforth
refer to the Credit Agreement as amended by this Amendment. This Amendment shall
be deemed incorporated into, and a part of, the Credit Agreement.


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                  (b)  This  Amendment   shall   be   binding upon and inure to
the benefit of the parties  hereto  and thereto and their respective successors
and assigns.  No third party beneficiaries are intended in connection with this
Amendment.

                  (c)  This Amendment shall be governed by and construed
in accordance with the law of the State of Illinois.

                  (d)  This   Amendment   may  be  executed  in  any  number  of
counterparts,  each  of  which  shall  be  deemed  an  original,  but  all  such
counterparts together shall constitute but one and the same instrument.  Each of
the parties  hereto  understands  and agrees that this  document  (and any other
document  required  herein) may be delivered by any party thereto  either in the
form  of an  executed  original  or  an  executed  original  sent  by  facsimile
transmission  to be followed  promptly by mailing of a hard copy  original,  and
that receipt by the Bank of a facsimile transmitted document purportedly bearing
the  signature of the Borrower  shall bind the Borrower  with the same force and
effect as the  delivery  of a hard copy  original.  Any  failure  by the Bank to
receive the hard copy executed  original of such document shall not diminish the
binding effect of receipt of the facsimile transmitted executed original of such
document which hard copy page was not received by the Bank.

                  (e)  This  Amendment,  together  with  the  Credit  Agreement,
contains the entire and exclusive agreement of the parties hereto with reference
to the matters discussed herein and therein. This Amendment supersedes all prior
drafts and  communications  with  respect  thereto.  This  Amendment  may not be
amended  except in accordance  with the provisions of Section 9.05 of the Credit
Agreement.

                  (f) If any term or provision of this Amendment shall be deemed
prohibited  by or invalid under any  applicable  law,  such  provision  shall be
invalidated without affecting the remaining  provisions of this Amendment or the
Credit Agreement, respectively.

                  (g) Borrower  covenants to pay to or reimburse the Bank,  upon
demand,  for all costs  and  expenses  (including  allocated  costs of  in-house
counsel) incurred in connection with the development,  preparation, negotiation,
execution and delivery of this Amendment.






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                  IN WITNESS  WHEREOF,  the  parties  hereto have  executed  and
delivered this Amendment as of the date first above written.



                            SPSS INC.


                            By:      /s/ Robert J. Brinkmann

                            Title:   Controller & Assistant Treasurer




                            BANK OF AMERICA ILLINOIS


                            By:     /s/ Cecily Person
                            Title:  Vice President