EXHIBIT 10(b)

                       SIXTH AMENDMENT TO CREDIT AGREEMENT
                           Dated as of August 10, 1993


     This SIXTH AMENDMENT TO CREDIT AGREEMENT, is dated as of August 10, 1993
(this "Amendment"), among SCIENCE APPLICATIONS INTERNATIONAL CORPORATION, a
Delaware corporation (the "Borrower"), CITIBANK, N.A. ("Citibank") and CITICORP
USA, INC. ("CUSA").

     PRELIMINARY STATEMENTS.  The Borrower and Citibank have entered into a
Credit Agreement dated as of October 31, 1988 (as amended by First Amendment
dated as of July 28, 1989, Second Amendment dated as of August 31, 1990, Third
Amendment dated as of July 1, 1991, Fourth Amendment dated as of June 30, 1992
and Fifth Amendment dated as of August 4, 1992, the "Credit Agreement").
Citibank wishes to assign its rights and obligations under the Credit Agreement
to CUSA, a wholly-owned subsidiary of Citibank, pursuant to Section 15.7 of the
Credit Agreement, and the parties hereto wish to amend the Credit Agreement in
certain respects as hereinafter set forth.  Terms defined in the Credit
Agreement are used in this Amendment as defined in the Credit Agreement and,
unless the context otherwise requires, all references to Sections and Exhibits
shall be deemed to refer to the corresponding Sections of and Exhibits to the
Credit Agreement.

     The parties hereto therefore agree as follows:

     SECTION 1.  ASSIGNMENT.  Effective as of the date hereof and subject to the
satisfaction of the conditions precedent set forth in Section 3 hereof, Citibank
shall sell and assign to CUSA and CUSA shall purchase and assume from Citibank
all of Citibank's rights and obligations under the Credit Agreement.  CUSA and
Citibank shall make arrangements among themselves with respect to the terms of
such assignment and assumption.  After giving effect to such assignment and
assumption, CUSA shall be a party to the Credit Agreement and shall have the
rights and obligations of Citibank thereunder and Citibank shall relinquish its
rights and be released from its obligations under the Credit Agreement and shall
cease to be a party thereto.

     SECTION 2.  AMENDMENTS.  Effective as of the date hereof and subject to the
satisfaction of the conditions precedent set forth in Section 3 hereof, the
Credit Agreement is amended as follows:

     a.   Section 2.3 shall be amended (i) by inserting the words "to cause
Citibank" after "the Bank" in the fourth line, (ii) by adding "and Citibank"
after "Borrower" in the final sentence, and (iii) by adding the following
sentence after the final sentence:

     "In the event that Citibank notifies the Bank that you have failed to pay
     any obligations under any Acceptance Agreement when due, you shall be
     deemed to have requested a Prime Rate Loan hereunder in the amount of such
     unpaid obligations and the Bank is hereby irrevocably authorized to make
     such a Prime



     Rate Loan and to deliver the proceeds thereof to Citibank for application
     to such obligations."

     b.   Section 2.4 shall be amended by adding "shall be in substantially the
form of Exhibit I hereto," after the parenthetical in the second sentence.

      c.  Section 8.5 shall be deleted and restated in its entirety as follows:

          8.5  PAYMENTS OF CERTIFIED AMOUNTS; OCCURRENCE OF SPECIFIED
     CONDITIONS.  Determination of amounts payable under Sections 4.5, 4.7, 5.5,
     5.7, 6.5, and 8.4 and Section 2 of Exhibit A in connection with a Fixed CD
     Rate Loan, a Eurodollar Loan or a Money Market Rate Loan, as the case may
     be, shall be calculated, and the existence of circumstances described in
     Section 8.6 shall be determined, as though the Bank funded such Loan by a
     borrowing from Citibank and that Citibank funded such borrowing through the
     purchase of an instrument of the type, maturity and amount corresponding to
     the instrument or index used as a reference in determining the rate of
     interest applicable to such Loan.

     d.   The definition of "Termination Date" in Section 15.1 is deleted and
restated in its entirety as follows:

          "TERMINATION DATE" shall mean July 1, 1996, or such anniversary of the
     date of this Agreement to which the Termination Date shall be extended
     pursuant to Section 15.14.

     e.   Section 15.14 shall be amended by deleting all references to "June 30"
and substituting therefor "July 31."

     f.   Section 1 of Exhibit A shall be amended by deleting the definition of
"Bank" and restating such definition in its entirety as follows:

          "BANK" shall mean Citicorp USA, Inc., a Delaware corporation.

     g.   Exhibit A shall be amended by inserting the following definition in
the appropriate alphabetical order in Section 1 thereof:

          "CITIBANK" shall mean Citibank, N.A., a national banking association.

     h.   The definitions of "Assessment Rate," "Eurodollar Rate," "Fixed CD
Rate," "Prime Rate" and "Reserve Percentage" in Section 1 of Exhibit A shall be
amended by deleting each reference to "the Bank" contained therein and
substituting "Citibank".

     i.   Section 5 of Exhibit A shall be deleted and restated in its entirety
as follows:



          5.  ADDRESS FOR NOTICES.  All notices sent or delivered to the Bank
     shall be addressed to the Bank at:  Citicorp USA, Inc., c/o Citicorp North
     America, Inc., 725 South Figueroa Street, Los Angeles, CA  90017, Attn:
     Michael Watchorn.

     j.   Exhibits C-1, C-2, D-1 and D-2 shall be deleted and replaced with
Exhibits C-1, C-2, D-1 and D-2 to this Amendment, respectively.

     k.   A new Exhibit I shall be added in the form of Exhibit I hereto.

     SECTION 3.  CONDITIONS TO EFFECTIVENESS.  This Amendment shall be effective
as of the date hereof, provided that (a) the representations and warranties
contained in Section 4 hereof are correct on and as of such date; (b) no event
has occurred and is continuing on such date which constitutes an Event of
Default or which would constitute an Event of Default but for the requirement
that notice be given or time elapse or both; and (c) CUSA shall have received
(i) counterparts of this Amendment executed by the Borrower and Citibank, (ii)
promissory notes of Borrower in the form attached as Exhibits C-1 and C-2
hereto, appropriately completed (the "Replacement Notes"), and (iii) a
certificate of the Secretary or an Assistant Secretary of the Borrower attaching
a copy of the resolutions of the Board of Directors of the Borrower authorizing
the execution and delivery of this Amendment and the Replacement Notes and
certifying the name and true signature of each officer of the Borrower executing
this Amendment or the Replacement Notes on its behalf.

     SECTION 4.  REPRESENTATIONS AND WARRANTIES.  The Borrower represents and
warrants as follows: (a) the Borrower is a corporation duly organized, validly
existing and in good standing under the laws of the jurisdiction indicated at
the beginning of this Amendment; (b) the execution, delivery and performance by
the Borrower of this Amendment and the Replacement Notes are within the
Borrower's corporate powers, have been duly authorized by all necessary
corporate action and do not contravene the Borrower's charter or by-laws, or
any law or any contractual restriction binding on or affecting the Borrower; (c)
no authorization, approval or other action by, and no notice to or filing with,
any governmental authority or regulatory body is required for the due execution,
delivery and performance by the Borrower of this Amendment and the Replacement
Notes; (d) this Amendment constitutes, and the Replacement Notes when executed
and delivered will constitute, the legal, valid and binding obligations of the
Borrower enforceable against the Borrower in accordance with their respective
terms; and (e) all representations and warranties of the Borrower set forth in
Section 13.1 of the Credit Agreement are true and correct as of the date first
stated above, as if repeated and restated in full herein.

     SECTION 5.  RETURN OF REVOLVING NOTES.  Promptly following the
effectiveness of Sections 1 and 2 hereof, Citibank shall return the



original Revolving Notes to the Borrower, marked "cancelled and replaced".

     SECTION 6.  REFERENCE TO AND EFFECT ON THE CREDIT AGREEMENT.  Upon the
effectiveness of Sections 1 and 2 hereof, on and after the date hereof, each
reference in the Credit Agreement to "this Agreement," "hereunder," "hereof,"
"herein" or words of like import shall mean and be a reference to the Credit
Agreement as amended by this Amendment, and each reference to "the Revolving
Notes" in the Credit Agreement shall mean and be a reference to the Replacement
Notes.   Except as specifically amended above, the Credit Agreement shall
continue to be in full force and effect and is hereby in all respects ratified
and confirmed.

     SECTION 7.  EXECUTION IN COUNTERPARTS.  This Amendment may be executed in
any number of counterparts and by any combination of the parties hereto in
separate counterparts, each of which counterparts shall be an original and all
of which taken together shall constitute one and the same Amendment.

     SECTION 8.  GOVERNING LAW.  This Amendment shall be governed by, and
construed in accordance with, the laws of the State of New York.

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed by their respective officers thereunto duly authorized, as of the date
first above written.


                                   SCIENCE APPLICATIONS INTERNATIONAL
                                        CORPORATION

                                   By    S/W. A. Roper
                                      -----------------------------
                                   Name  William A. Roper, Jr.
                                        ---------------------------
                                   Title  Sr. V.P./CFO
                                         --------------------------


                                   By   S/Ward Reed
                                      -----------------------------
                                   Name    Ward Reed
                                        ---------------------------
                                   Title   Corp. V.P. & Treasurer
                                         --------------------------


                                   CITIBANK, N.A.

                                   By:  S/Edward Lettieri
                                      ---------------------------------
                                        Vice President


                                   CITICORP USA, INC.

                                   By:  S/Carolyn R. Bodmer
                                      ---------------------------------
                                        Vice President



                                   EXHIBIT C-1

                             REVOLVING DOMESTIC NOTE


U.S. $
      ---------------------                   ----------------------------------
                                                                   , 19
                                              ---------------------    ---------


          [NAME OF BORROWER], a [jurisdiction of incorporation] corporation (the
"Borrower"), FOR VALUE RECEIVED, hereby promises to pay to the order of CITICORP
USA, INC. (the "Bank") at the office of Citibank, N.A. located at 399 Park
Avenue, New York, New York, (i) the principal amount of each Revolving Loan made
by the Bank to the Borrower as a Domestic Loan pursuant to the Agreement
referred to below on the last day of the Interest Period (as defined in the
Agreement) applicable thereto and (ii) on the Termination Date (as defined in
the Agreement) the principal sum of __________________________ Dollars, or if
less, the aggregate unpaid principal amount of the Revolving Loans made by the
Bank to the Borrower as Domestic Loans pursuant to the Agreement, in each case
in lawful money of the United States of America (in freely transferable U.S.
dollars and in immediately available funds).

          The Borrower promises also to pay interest on the unpaid principal
amount hereof in like money at said office from the date hereof until paid at
the rates per annum which shall be determined in accordance with the provisions
of the Credit Agreement dated as of October 31, 1988, between Science
Applications International Corporation and the Bank (as amended by First
Amendment dated as of July 28, 1989, Second Amendment dated as of August 31,
1990, Third Amendment dated as of July 1, 1991, Fourth Amendment dated as of
June 30, 1992, Fifth Amendment dated as of August 4, 1992, and Sixth Amendment
dated as of July 30, 1993, and as it may be further amended from time to time,
the "Agreement"), said interest to be payable at the times provided for in the
Agreement.

          This Note is one of the Revolving Domestic Notes referred to in the
Agreement and is entitled to the benefits thereof.  As provided in the
Agreement, this Note is subject to prepayment, in whole or in part, as specified
in the Agreement.  In case an Event of Default (as defined in the Agreement)
shall occur and be continuing, the principal of and accrued interest on this
Note may be declared to be due and payable in the manner and with the effect
provided in the Agreement.

          The Borrower hereby waives presentment, demand, protest or notice of
any kind in connection with this Note.



          [This Note is issued in replacement for the Revolving Domestic Note of
the Borrower dated October 31, 1988.]1

          [Science Applications International Corporation has, pursuant to the
provisions of the Agreement, guaranteed the payment in full of the principal of
and interest on this Note.]2


                                   [NAME OF BORROWER]


                                   By
                                      -----------------------------


    1 To be deleted in the case of a Note issued by a Borrowing  Subsidiary.

    2 To be deleted in the case of a Note issued by the Company.



                                   EXHIBIT C-2

                            REVOLVING EURODOLLAR NOTE


U.S. $
      ---------------------                   ----------------------------------
                                                                   , 19
                                              ---------------------    ---------


          [NAME OF BORROWER], a [jurisdiction of incorporation] corporation (the
"Borrower"), FOR VALUE RECEIVED, hereby promises to pay to the order of CITICORP
USA, INC. (the "Bank") at the office of Citibank, N.A. located at 399 Park
Avenue, New York, New York, (i) the principal amount of each Revolving Loan made
by the Bank to the Borrower as a Eurodollar Loan pursuant to the Agreement
referred to below on the last day of the Interest Period (as defined in the
Agreement) applicable thereto and (ii) on the Termination Date (as defined in
the Agreement) the principal sum of __________________________ Dollars, or if
less, the aggregate unpaid principal amount of the Revolving Loans made by the
Bank to the Borrower as Eurodollar Loans pursuant to the Agreement, in each case
in lawful money of the United States of America (in freely transferable U.S.
dollars and in immediately available funds).

          The Borrower promises also to pay interest on the unpaid principal
amount hereof in like money at said office from the date hereof until paid at
the rates per annum which shall be determined in accordance with the provisions
of the Credit Agreement dated as of October 31, 1988, between Science
Applications International Corporation and the Bank (as amended by First
Amendment dated as of July 28, 1989, Second Amendment dated as of August 31,
1990, Third Amendment dated as of July 1, 1991, Fourth Amendment dated as of
June 30, 1992, Fifth Amendment dated as of August 4, 1992, and Sixth Amendment
dated as of July 30, 1993, and as it may be further amended from time to time,
the "Agreement"), said interest to be payable at the times provided for in the
Agreement.

          This Note is one of the Revolving Eurodollar Notes referred to in the
Agreement and is entitled to the benefits thereof.  As provided in the
Agreement, this Note is subject to prepayment, in whole or in part, as specified
in the Agreement.  In case an Event of Default (as defined in the Agreement)
shall occur and be continuing, the principal of and accrued interest on this
Note may be declared to be due and payable in the manner and with the effect
provided in the Agreement.

          The Borrower hereby waives presentment, demand, protest or notice of
any kind in connection with this Note.



          [This Note is issued in replacement for the Revolving Eurodollar Note
of the Borrower dated October 31, 1988.]1

          [Science Applications International Corporation has, pursuant to the
provisions of the Agreement, guaranteed the payment in full of the principal of
and interest on this Note.]2


                                   [NAME OF BORROWER]


                                   By
                                      -----------------------------------------
                                   Title
                                         -------------------------


    1 To be deleted in the case of a Note by a Borrowing Subsidiary.

    2 To be deleted in the case of a Note issued by the Company.



                                   EXHIBIT D-1

                               TERM DOMESTIC NOTE

U.S. $
       --------------------                            -------------------------
                                                                            , 19
                                                       ---------------------


          [NAME OF BORROWER], a [jurisdiction of incorporation] corporation (the
"Borrower"), FOR VALUE RECEIVED, hereby promises to pay to the order of CITICORP
USA, INC. (the "Bank") at the office of Citibank, N.A. located at 399 Park
Avenue, New York, New York, (i) the principal amount of each Term Loan made by
the Bank to the Borrower as a Domestic Loan pursuant to the Agreement referred
to below on the last day of the Interest Period (as defined in the Agreement)
applicable thereto, PROVIDED that the Borrower shall reduce the aggregate
principal amount of all Term Loans outstanding hereunder by making twelve
substantially equal quarter-annual payments of principal (from sources other
than proceeds of Term Loans) on the last Business Day (as defined in the
Agreement) of each January, April, July and October of each year, commencing
with the first such date to occur after the Termination Date (as defined in the
Agreement), and with a final payment of all unpaid principal on the third
anniversary of the Termination Date.

          The Borrower promises also to pay interest on the unpaid principal
amount thereof in like money at said office from the date hereof until paid at
the rates per annum which shall be determined in accordance with the provisions
of the Credit Agreement dated as of October 31, 1988, between Science
Applications International Corporation and the Bank (as amended by First
Amendment dated as of July 28, 1989, Second Amendment dated as of August 31,
1990, Third Amendment dated as of July 1, 1991, Fourth Amendment dated as of
June 30, 1992, Fifth Amendment dated as of August 4, 1992, and Sixth Amendment
dated as of July 30, 1993, and as it may be further amended from time to time,
the "Agreement"), said interest to be payable at the times provided for the
Agreement.

          This Note is one of the Term Domestic Notes referred to in the
Agreement and is entitled to the benefits thereof.  As provided in the
Agreement, this Note is subject to prepayment, in whole or in part, as specified
in the Agreement.  In case an Event of Default (as defined in the Agreement)
shall occur and be continuing, the principal of and accrued interest on this
Note may be declared to be due and payable in the manner and with the effect
provided in the Agreement.

          The Borrower hereby waives presentment, demand, protest or notice of
any kind in connection with this Note.



          [Science Applications International Corporation has, pursuant to the
provisions of the Agreement, guaranteed the payment in full of the principal of
and interest on this Note.]1


                              [NAME OF BORROWER]


                              By
                                 --------------------------------
                                   Title:

- ------------------------
    1 To be deleted in the case of a Note issued by the Company.



                                   EXHIBIT D-2

                              TERM EURODOLLAR NOTE

U.S. $
       --------------------                            -------------------------
                                                                            , 19
                                                       ---------------------


          [NAME OF BORROWER], a [jurisdiction of incorporation] corporation
(the "Borrower"), FOR VALUE RECEIVED, hereby promises to pay to the order of
CITICORP USA, INC. (the "Bank") at the office of Citibank, N.A. located at 399
Park Avenue, New York, New York, (i) the principal amount of each Term Loan made
by the Bank to the Borrower as a Eurodollar Loan pursuant to the Agreement
referred to below on the last day of the Interest Period (as defined in the
Agreement) applicable thereto, PROVIDED that the Borrower shall reduce the
aggregate principal amount of all Term Loans outstanding hereunder by making
twelve substantially equal quarter-annual payments of principal (from sources
other than proceeds of Term Loans) on the last Business Day (as defined in the
Agreement) of each January, April, July and October of each year, commencing
with the first such date to occur after the Termination Date (as defined in the
Agreement), and with a final payment of all unpaid principal on the third
anniversary of the Termination Date.

          The Borrower promises also to pay interest on the unpaid principal
amount thereof in like money at said office from the date hereof until paid at
the rates per annum which shall be determined in accordance with the provisions
of the Credit Agreement dated as of October 31, 1988, between Science
Applications International Corporation and the Bank (as amended by First
Amendment dated as of July 28, 1989, Second Amendment dated as of August 31,
1990, Third Amendment dated as of July 1, 1991, Fourth Amendment dated as of
June 30, 1992, Fifth Amendment dated as of August 4, 1992, and Sixth Amendment
dated as of July 30, 1993, and as it may be further amended from time to time,
the "Agreement"), said interest to be payable at the times provided for the
Agreement.

          This Note is one of the Term Eurodollar Notes referred to in the
Agreement and is entitled to the benefits thereof.  As provided in the
Agreement, this Note is subject to prepayment, in whole or in part, as specified
in the Agreement.  In case an Event of Default (as defined in the Agreement)
shall occur and be continuing, the principal of and accrued interest on this
Note may be declared to be due and payable in the manner and with the effect
provided in the Agreement.

          The Borrower hereby waives presentment, demand, protest or notice of
any kind in connection with this Note.



          [Science Applications International Corporation has, pursuant to the
provisions of the Agreement, guaranteed the payment in full of the principal of
and interest on this Note.]1


                              [NAME OF BORROWER]


                              By
                                 --------------------------------
                                   Title:


    1 To be deleted in the case of a Note issued by the Company.



                                    EXHIBIT I

                               NOTICE OF BORROWING


[Date]

CITICORP USA, INC.
c/o Citicorp North America, Inc.
725 South Figueroa Street, Fifth Floor
Los Angeles, CA  90017
Attention: Michael Watchorn

Ladies and Gentlemen:

     Pursuant to the Credit Agreement between you and Science Applications
International Corporation dated as of October 31, 1988 (as amended through the
date hereof, the "Credit Agreement;" all terms defined therein being used with
the same meanings), the undersigned, _________________________________ (the
"Borrower"), hereby notifies you of the Borrower's request for a Loan under the
Credit Agreement as follows:

     1.   The amount of such Loan shall be $                    .
                                            --------------------

     2.   The date of borrowing of such Loan shall be                  , 19    .
                                                      -----------------    ----

     3.   Such Loan shall be a:

               Prime Rate Loan with an Interest Period of      days.
     -------                                              ----


               Eurodollar Rate Loan with an Interest Period of
     ----------                                                -----------
               months.

               Fixed CD Rate Loan with an Interest Period of       days.
     -------                                                 ------

               Money Market Rate Loan with an interest rate of
     -------
                             % per annum and a maturity date of
               --------------
                                     , 19   .
               ------------------ ---    ---

     4.   $             of the proceeds of such Loan will be used by the
           ------------
Borrower to purchase or carry Margin Stock [if none insert "NONE"].



     Pursuant to Section 9 of the Credit Agreement, the  undersigned hereby
certifies that:

     (a) there exists no Event of Default and all representations and warranties
contained in the Credit Agreement (excluding those contained in subsections (c)
and (e) of Section 13.1 thereof) are true and correct as of the date hereof,
both before and after giving effect to such Loan; and

     (b) if such Loan increases the outstanding principal amount of Revolving
Loans to the Borrower or if this Notice is given in connection with the making
of the initial Term Loans to the Borrower, there exists no Default or Event of
Default and all representations and warranties contained in the Credit Agreement
are true and correct as of the date hereof, both before and after giving effect
to such Loan.


                                        Very truly yours,


                                        [NAME OF BORROWER]

                                        By
                                            -----------------------------
                                        Title
                                               --------------------------