SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549


SCHEDULE 13G
Under the Securities Exchange Act of 1934

A fee is being paid with this statement.

Name of
Issuer:  MORRISON KNUDSEN CORP
         ____________________________________________________________________

Title of Class
of Securities:  Common Stock

CUSIP Number:   618447106


 1)  NAME OF I.R.S. IDENTIFICATION NO. OF REPORTING PERSON

     The Prudential Insurance Company of America    22-1211670

 2)  MEMBER OF A GROUP:  (a)  N/A
                         (b)  N/A

 3)  SEC USE ONLY:




 4)  PLACE OF ORGANIZATION:  A mutual insurance company organized
                             under the laws of the State of New Jersey

NUMBERS OF SHARES BENEFICIALLY OWNED BY REPORTING PERSON WITH:

 5)  Sole Voting Power:             14,500    See Exhibit A 
 6)  Shared Voting Power:        1,653,700    SEE EXHIBIT A 
 7)  Sole Dispositive Power:        14,500    See Exhibit A 
 8)  Shared Dispositive Power:   1,654,500    See Exhibit A 

 9)  AGGREGATE AMOUNT BENEFICIALLY OWNED:  1,669,000 See Exhibit A

10)  AGGREGATE AMOUNT IN ROW (9) EXCLUDES SHARES:  N/A

11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):  5.0See Exhibit A

12)  TYPE OF REPORTING PERSON:  BD, IC, IA

ITEM 1(a).  NAME OF ISSUER:

            MORRISON KNUDSEN CORP

ITEM 1(b).  ADDRESS OF ISSUER'S EXECUTIVE OFFICES:

            One Morrison Knudsen Plaza
            720 Park Blvd
            Boise, ID  83729

ITEM 2(a).  NAME OF PERSON FILING:

            The Prudential Insurance Company of America

ITEM 2(b).  ADDRESS OF PRINCIPAL BUSINESS OFFICE:

            Prudential Plaza
            Newark, New Jersey  07102-3777

ITEM 2(c).  CITIZENSHIP:

            A mutual insurance company organized under the laws
            of the State of New Jersey

ITEM 2(d).  TITLE OF CLASS SECURITIES:

            Common Stock

ITEM 2(e).  CUSIP NUMBER:

            618447106

ITEM 3.     The Person filing this statement is an Insurance Company
            as defined in Section 3(a)(19) of the Securities Exchange
            Act of 1934, a Broker-Dealer registered under Section 15
            of that Act and an Investment Adviser registered under
            Section 203 of the Investment Advisers Act of 1940.

ITEM 4.     OWNERSHIP:

            (a) Number of Shares
                Benefically Owned:           1,669,000  See Exhibit A  

            (b) Percent of Class:    5.0   See Exhibit A

                                                   Number
            (c) Powers                          Of Shares
                ---------------------           ---------
                Sole power to vote or              14,500   See Exhibit A 
                to direct the vote

                Shared power to vote or         1,653,700   SEE EXHIBIT A 
                to direct the vote

                Sole power to dispose or           14,500   See Exhibit A 
                to direct disposition

                Shared power to dispose         1,654,500   See Exhibit A 
                or to direct disposition


ITEM 5.     OWNERSHIP OF 5% OR LESS OF A CLASS:

            Not Applicable

ITEM 6.     OWNERSHIP OF MORE THAN 5% ON BEHALF OF ANOTHER PERSON:

            See Exhibit A

ITEM 7.     IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY
            WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE
            ULTIMATE PARENT COMPANY:

            Not Applicable

ITEM 8.     IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP:

            Not Applicable

ITEM 9.     NOTICE OF DISSOLUTION OF GROUP:

            Not Applicable

ITEM 10.    CERTIFICATION:

            By signing below, The Prudential Insurance Company of America
            certifies that, to the best of its knowledge and belief, the
            securities referred to above were acquired in the ordinary course
            of business and were note acquired for the purpose of and do not
            have the effect of changing or influencing the control of the
            issuer of such securities and were not acquired in connection
            with or as a participant in any transaction having such purpose
            or effect.

            The filing of this statement should not be construed as an
            admission that Prudential is or was for the purposes of Section
            13(d) or 13(g) of the Securities Exchange Act of 1934, the
            beneficial owner of any registered equity securities of the issuer.



                                   SIGNATURE

                 After reasonable inquiry and to the best of its knowledge and
             belief, The Prudential Insurance Company of America certifies that
             the information set forth in this statement is true, complete and
             correct.


             THE PRUDENTIAL INSURANCE COMPANY OF AMERICA

             By:  Richard S. Biegen
                  Assistant General Counsel

             Date:   February 7, 1995

             As of:  December 31, 1994


                                   Exhibit A
                                   ---------

ITEM 6.     OWNERSHIP OF MORE THAN 5% ON BEHALF OF ANOTHER PERSON:
            ------------------------------------------------------
            The Prudential Insurance Company of America ("Prudential") may have
            direct or indirect voting and/or investment discretion over
            1,669,000 shares of the Issuer's common stock which are held for
            the benefit of its clients by its separate accounts, externally
            managed accounts, registered investment companies, subsidiaries
            and/or other affiliates.  Prudential is reporting the combined
            holdings of these entities for the purpose of administrative
            convenience.   
             
            These shares were acquired in the ordinary course of business, and
            not with the purpose or effect of changing or influencing control
            of the Issuer.  The filing of this statement should not be
            construed as an admission that Prudential is, for the purposes of
            Sections 13 or 16 of the Securities Exchange Act of 1934, the
            beneficial owner of these shares.