Exhibit 4.2

                           Dated as of March 3, 1999



Teachers Insurance and Annuity
  Association of America
730 Third Avenue
New York, New York  10017

AmerUs Life Insurance Company
c/o Amerus Capital Management
699 Walnut Street, Suite 1700
Des Moines, Iowa  50309-3945

Modern Woodmen of America
1701 First Avenue
Rock Island, Illinois  61201

Ladies and Gentlemen:

         Reference is made to those certain Note Purchase Agreements between
Hutchinson Technology Incorporated, a Minnesota corporation (the "Company"), and
each of Teachers Insurance and Annuity Association of America, Central Life
Assurance Company and Modern Woodmen of America (collectively, the
"Purchasers"), each dated as of April 20, 1994 (as heretofore amended or
otherwise modified, the "Agreements"), pursuant to which the Purchasers
purchased the 7.46% Senior Notes of the Company in the aggregate original
principal amount of $30,000,000 (the "Notes"). The addressees of this letter
agreement (collectively, the "Noteholders") are the registered holders of 100%
of the aggregate outstanding principal amount of the Notes as reflected in the
Note Register required to be maintained by the Company pursuant to Section 10.1
of each of the Agreements, and the Noteholders whose signatures are affixed
below hold 100% of the aggregate unpaid principal amount of the Notes
outstanding as of the date hereof.

         The Company has informed the Noteholders that it desires to amend the
Agreements in certain respects as of the date hereof, and the Noteholders have
agreed to such amendments as more fully described below in this letter agreement
("this Amendment").

         Now, therefore, the Company and the Noteholders (by their acceptance
hereof) hereby agree as follows:

         1.       AMENDMENTS.

         The Agreements will be amended as hereafter in this paragraph 1 set
forth, such amendments to become effective as provided in paragraph 3 hereof:



         (a)      Section 3.1 of the Agreements shall be amended to be and 
read in its entirety as follows:

         "3.1. PREPAYMENTS AND PAYMENT AT MATURITY. On August 15, 1996 and on
         each February 15 and August 15 thereafter to and including August 15,
         2003 (so long as any Notes shall remain outstanding), the Company will
         prepay, and there shall become due and payable, $1,875,000.00 in
         principal amount of the Notes (or such lesser principal amount of Notes
         as shall then be outstanding). Each such prepayment pursuant to this
         Section shall be at 100% of the principal amount so to be prepaid
         together with interest accrued thereon to the date of such prepayment,
         without premium. Upon the prepayment on any date of less than the
         entire outstanding principal amount of the Notes pursuant to SECTION
         3.2 or SECTION 3.8, the principal amount of the Notes required to be
         prepaid on any February 15 or August 15 thereafter pursuant to this
         Section shall be reduced in the same proportion as the aggregate
         principal amount of the Notes outstanding immediately prior to said
         prepayment pursuant to SECTION 3.2 or SECTION 3.8 shall have been
         reduced by said prepayment. The Company will, in the event of any such
         reduction pursuant to the immediately preceding sentence, promptly
         after the prepayment of Notes giving rise to such reduction, furnish
         each holder of Notes with notice thereof setting forth the Company's
         calculation of the respective required prepayments and payment at final
         maturity due thereafter pursuant to this Section (giving effect to such
         reduction). On February 15, 2004, the Company will pay, and there shall
         become due and payable, the entire remaining unpaid principal amount of
         the Notes, together with interest accrued thereon.

         (b) Section 3.4 of the Agreements shall be amended to be and read in
its entirety as follows:

                  "3.4. ALLOCATION OF PARTIAL PREPAYMENTS. In the case of each
         prepayment, whether required or optional, of less than the entire
         unpaid principal amount of all outstanding Notes (other than any such
         prepayment pursuant to SECTION 3.8 in connection with the acceptance by
         one or more holders of Notes of a Prepayment Offer referred to in
         SECTION 3.8), the principal amount of the Notes so to be prepaid shall
         be allocated among all of the Notes at the time outstanding in
         proportion, as nearly as practicable, to the respective principal
         amounts thereof not theretofore prepaid."

         (c) Section 3.5 of the Agreements shall be amended to be and read in
its entirety as follows:

                  "3.5. MATURITY; SURRENDER, ETC. In the case of each prepayment
         of Notes, the principal amount of each Note to be prepaid shall become
         due and payable on the date fixed for such prepayment in this Agreement
         (if such prepayment is to be made pursuant to SECTION 3.1) or in the
         notice of such prepayment pursuant to SECTION 3.3 (if such prepayment
         is to be made pursuant to SECTION 3.2) or in the Trust Agreement
         referred to in SECTION 3.8 (if such prepayment is to made pursuant to
         SECTION 3.8), together with


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         interest accrued on such principal amount to such date and the
         Makewhole Amount, if any, payable in connection with such prepayment.
         Any Note paid or prepaid in full shall thereafter be surrendered to the
         Company upon its written request therefor and cancelled and not
         reissued."

         (d) Section 3 of the Agreements shall be further amended by adding
thereto, following Section 3.7 thereof, a new Section 3.8, which new Section
shall be and read in its entirety as follows:

                  "3.8. PREPAYMENT OF NOTES PURSUANT TO TRUST AGREEMENT. The
         Company shall be required to prepay Notes of each holder thereof which
         shall have given notice of such holder's acceptance of a Prepayment
         Offer made by the Company pursuant to (and as the term `Prepayment
         Offer' is defined in) Section 7.2(b) of that certain Trust Agreement,
         dated as of March 3, 1999 (as from time to time supplemented and
         amended and in effect, the "TRUST AGREEMENT"), between the Company and
         U.S. Bank Trust National Association, a national banking association,
         as trustee thereunder (together with its successors as such trustee,
         the "TRUSTEE") for the equal and ratable benefit and security of the
         holders from time to time of the Notes and the holders from time to
         time of the Company's 1996 Notes referred to (and as the term `1996
         Notes' is defined) in the Trust Agreement, each such prepayment to be
         made at the price and on the date determined in accordance with, and
         otherwise as provided in, said Section 7.2(b) of the Trust Agreement."

         2. REPRESENTATIONS AND WARRANTIES. The Company represents and warrants
and covenants to and for the benefit of the Noteholders as follows:

         (a) The execution and delivery by the Company of this Amendment and the
performance by the Company of this Amendment and of the Agreements and the Notes
as amended hereby (i) have been duly authorized by all requisite corporate
action on the part of the Company (no action on the part of the shareholders of
the Company being required therefor), (ii) do not require the consent or
approval of (A) any Governmental Body, or (B) except as set forth below, any
other Person, and (iii) do not and will not (A) violate (1) any provision of any
law, statute, rule or regulation or of the articles of incorporation or by-laws
of the Company, (2) any Order of any court, administrative body or arbitrator or
any rule, regulation or Order of any Governmental Body binding upon the Company
or any of its properties, or (3) any provision of any loan or credit agreement,
indenture, mortgage or other agreement or instrument to which the Company is a
party or by which it or any of its properties are or may be bound, or (B) result
in any breach of or constitute (alone or with notice or lapse of time or both) a
default under any such loan or credit agreement, indenture, mortgage or other
agreement or instrument.

         (b) This Amendment, and the Agreements as amended hereby, constitute
the legal, valid and binding obligations and agreements of the Company,
enforceable against the Company in accordance with their respective terms,
except as such enforcement may be limited by


                                      3



         applicable bankruptcy, insolvency, reorganization, moratorium or
         similar laws or equitable principles relating to or limiting creditors'
         rights generally.

         (c) As of the date hereof, and after giving effect to the amendments to
the Agreements effected by this Amendment, no Default or Event of Default has
occurred and is continuing under and within the meaning of the Agreements.

         3. EFFECTIVENESS. The amendments to the Agreements provided for in this
Amendment shall become effective upon the execution and delivery of counterparts
of this Amendment by the Company and the holders of 100% in aggregate principal
amount of Notes at the time outstanding (as provided in Section 12(a) of the
Agreements).

         4. MISCELLANEOUS. Except as specifically amended hereby, all terms and
provisions of each of the Agreements shall remain in full force and effect.
Without limiting the provisions of Section 15.1 of the Agreements, the Company
will pay all expenses incurred by each Noteholder in connection with this
Amendment. This Amendment may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which taken together shall
constitute one and the same instrument. Capitalized terms used but not otherwise
defined in this Amendment shall have the meanings assigned to them by each of
the Agreements.


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         If you are in agreement with the foregoing, please so indicate by
executing the form of acknowledgment set forth below, whereupon this Amendment
shall become a binding agreement effective as of the date hereof.

                           Very truly yours,

                           HUTCHINSON TECHNOLOGY
                           INCORPORATED

                           By   /s/ John A. Ingleman
                              --------------------------------

                              Its     CFO
                                 -----------------------------

Agreed to and accepted as of the date first above written.

TEACHERS INSURANCE AND ANNUITY
  ASSOCIATION OF AMERICA

By   /s/ Diane Hom                                   
  ---------------------------------------------

  Its   Director-Private Placements
     ------------------------------------------

AMERUS LIFE INSURANCE COMPANY

By   /s/ Roger D. Fors                               
  ---------------------------------------------

  Its   Vice President                           
     ------------------------------------------

MODERN WOODMEN OF AMERICA

By   /s/ Nick S. Coin                                
  ---------------------------------------------

  Its Manager, Securities Division               
      -----------------------------------------