Exhibit 10.21

                       AMENDMENT NO. 4 TO CREDIT AGREEMENT

        AMENDMENT NO. 4 dated as of September 30, 1998 among PERINI  CORPORATION
(the "Borrower"),  the BANKS listed on the signature pages hereof (collectively,
the  "Banks")  and MORGAN  GUARANTY  TRUST  COMPANY  OF NEW YORK,  as Agent (the
"Agent").

                              W I T N E S S E T H:

        WHEREAS, the Borrower, the Banks and the Agent are parties to an Amended
and  Restated  Credit  Agreement  dated as of January  17,  1997 (as  heretofore
amended, the "Credit Agreement");

        WHEREAS,  the  Borrower  has  requested  an  amendment  to the  covenant
limiting  Real  Estate  Investments  contained  in  Section  5.15 of the  Credit
Agreement;

        NOW, THEREFORE, the parties hereto agree as follows:

        SECTION  1.  Definitions;   References.  Unless  otherwise  specifically
defined herein,  each term used herein which is defined in the Credit  Agreement
shall  have the  meaning  assigned  to such term in the Credit  Agreement.  Each
reference to "hereof", "hereunder", "herein" and "hereby" and each other similar
reference  and  each  reference  to "this  Agreement"  and  each  other  similar
reference contained in the Credit Agreement shall from and after the date hereof
refer to the Credit Agreement as amended hereby.

        SECTION 2.  Amendment  of Covenant  Limiting  Real  Estate  Investments.
Section 5.15 of the Credit  Agreement is amended to change the maximum amount of
Real Estate Investments permitted during the fiscal year ended December 31, 1998
from $7,650,000 to $9,550,000.

        SECTION 3.  Reduction of  Commitments.  Effective as of the date hereof,
the unused portions of the  Commitments  shall be permanently  reduced,  ratably
among the Banks, by the aggregate amount of $2,900,000.  This reduction shall be
applied  first to reduce  the  Tranche B  Commitments  of the Banks  ratably  in
proportion to their  respective  Tranche B  Commitments  and, once the Tranche B
Commitments are reduced to zero, then to reduce the Tranche A Commitments of the
Banks  ratably  in  proportion  to  their  respective   Tranche  A  Commitments.
Notwithstanding the provisions of Section 2.10(b) of the Credit Agreement,  this
reduction  shall not reduce the amount of reduction in  Commitments  required on
the Commitment Reduction Date occurring in December,  1998, but instead shall be
applied to reduce the aggregate  amount of reduction in Commitments  required on
the last Commitment  Reduction  Date.  This Amendment  constitutes the notice of
such reduction required by Section 2.09 of the Credit Agreement.

        SECTION 4.  Representations  and  Warranties  Correct;  No Default.  The
Borrower and each Subsidiary Guarantor represents and warrants that on and as of
the date hereof, after giving effect to this Amendment,  (a) the representations
and warranties of each Obligor contained in each Financing Document, as amended,
to which it is a party are true and (b) no Default  under the  Credit  Agreement
exists.

        SECTION 5. Effect of  Amendments.  Except as expressly set forth herein,
the amendments  contained  herein shall not constitute an amendment or waiver of
any  term  or  condition  of the  Credit  Agreement  or of any  other  Financing
Document,  and all such  terms and  conditions  shall  remain in full  force and
effect and are hereby ratified and confirmed in all respects.

        SECTION 6.  Governing  Law.  This  Amendment  shall be  governed  by and
construed in accordance with the laws of the State of New York.



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                                                                   Exhibit 10.21


        SECTION 7.  Counterparts.  This Amendment may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument.

        SECTION 8. Consent by Subsidiary  Guarantors.  By signing this Amendment
below,  each Subsidiary  Guarantor  affirms its obligations under the Subsidiary
Guarantee  Agreement  and  acknowledges  that this  Amendment  shall not  alter,
release,  discharge or otherwise  affect any of such  obligations,  all of which
shall remain in full force and effect and are hereby  ratified and  confirmed in
all respects.

        SECTION 9.  Effectiveness.  This Amendment shall become  effective as of
the date  hereof  when  the  Agent  shall  have  received:  (a)  dully  executed
counterparts  hereof signed by the Borrower,  the Required Banks,  the Agent and
each Subsidiary  Guarantor (or, in the case of any party as to which an executed
counterpart  shall  not have  been  received,  the  Agent  shall  have  received
telegraphic, telex or other written confirmation from such party of execution of
a  counterpart  hereof by such party) and (b) for the account of each Bank,  the
fee required to be paid under Section 3 of this Amendment.

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




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