<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                               -------------------
                                FORM 10-K/A NO. 1

         ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
         EXCHANGE ACT OF 1934
           For the Fiscal Year Ended             Commission File Number
             September 30, 1999                         0-24934


                              PRI AUTOMATION, INC.
             (Exact name of registrant as specified in its charter)



                    Massachusetts                          04-2495703
         (State or other jurisdiction of                (I.R.S. Employer
         incorporation)                                 Identification No.)

              805 Middlesex Turnpike                          01821
                  Billerica, MA                             (Zip Code)
         (Address of principal executive offices)



                  Registrant's telephone number: (978) 670-4270

                               -------------------

           Securities registered pursuant to Section 12(b) of the Act:
                          COMMON STOCK, PAR VALUE $.01
           Securities registered pursuant to Section 12(g) of the Act:
                                      NONE

                               -------------------

         Indicate by check mark whether the Registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
Registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes X No _____

         Indicate by check mark if disclosure of delinquent filers pursuant to
Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of Registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K. /x/

         The aggregate market value of the voting stock held by non-affiliates
of the Registrant, based on the closing price of the Common Stock on December 3,
1999 as reported by the Nasdaq National Market, was approximately
$1,091,299,458. Shares of Common Stock held by each executive officer and
director of the Registrant and by each person known by the Registrant to own
beneficially 5% or

<PAGE>


more of the outstanding Common Stock have been excluded from this computation in
that such persons may be deemed to be affiliates. That such persons have been
deemed affiliates for purposes of this computation should not be considered a
conclusive determination for any other purpose.

         As of December 3, 1999, the Registrant had outstanding 22,612,092
shares of Common Stock.

                       DOCUMENTS INCORPORATED BY REFERENCE
                                      NONE


<PAGE>


         THE FOLLOWING ITEMS ARE INCLUDED HEREIN: ITEMS 10, 11, 12 AND 13.

EXPLANATION FOR THIS AMENDMENT:

         The Annual Report on Form 10-K of PRI Automation, Inc. (the "Company")
for the Company's fiscal year ended September 30, 1999 (the "1999 Form 10-K") is
being amended hereby to include the items listed below:

ITEM     DESCRIPTION

Item 10  Directors and Executive Officers of the Registrant

Item 11  Executive Compensation

Item 12  Security Ownership of Certain Beneficial Owners and Management

Item 13  Certain Relationships and Related Transactions

         The Company's 1999 Form 10-K, as originally filed with the Securities
and Exchange Commission (the "Commission") on December 23, 1999, incorporated
into such form the information required by Items 10, 11, 12 and 13 of Form 10-K
by reference to the Company's Definitive Proxy Statement for its 2000 Annual
Meeting of Stockholders (the "Proxy Statement"). The Proxy Statement was not
filed with the Commission within 120 days of the close of the Company's fiscal
year ended September 30, 1999, however. Accordingly, the 1999 Form 10-K is being
amended hereby to include the information that was originally expected to be
incorporated by reference.

THE AMENDMENT

         Items 10, 11, 12 and 13 in Part III of the 1999 Form 10-K are hereby
amended by deleting the texts thereof in their entirety and substituting
therefor the following:

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

                        DIRECTORS AND EXECUTIVE OFFICERS

         The following table sets forth certain information concerning each
director (each of whom has been nominated for re-election) and each executive
officer of PRI:


<TABLE>
<CAPTION>

            NAME                 AGE                                   POSITION
            ----                 ---                                   --------


<S>                               <C> <C>
Mordechai Wiesler                 69  Chairman of the Board of Directors
Mitchell G. Tyson                 45  President, Chief Executive Officer and Director
Stephen D. Allison (1)            54  Chief Financial Officer
Robert G. Postle                  45  Vice President, General Manager, Factory Systems Division
Edward A. Wagner                  51  Vice President, General Manager, OEM Systems Division
Amram Rasiel (2)                  69  Director
Boruch B. Frusztajer (2)(3)       69  Director
Alexander V. d'Arbeloff (3)       72  Director
Kenneth M. Thompson               61  Director

</TABLE>

<PAGE>

-----------------
(1)      Mr. Allison has resigned effective January 28, 2000.
(2)      Member of the Audit Committee
(3)      Member of the Compensation Committee

         MORDECHAI WIESLER, a founder of PRI, has been a director of PRI since
our inception. Mr Wiesler served as PRI's President from our inception until
February 1995, as Chief Executive Officer from our inception until August 1998
and as Treasurer from our inception until September 1999. Mr. Wiesler was also
the founder, president and chairman of Transistor Automation Corporation until
its sale to Teledyne, Inc. in 1966. Mr Wiesler received a B.S. in mechanical
engineering from the Technion in Israel.

         MITCHELL G. TYSON was named Chief Executive Officer of PRI in August
1998. He was elected to the office of President and named a director of PRI in
1995. Mr. Tyson served as our Chief Operating Officer from 1990 to 1998. From
1987 to 1990, he served as our Vice President, Operations. From 1984 to 1987,
Mr. Tyson was the director of product management of GCA Corporation, a
manufacturer of semiconductor capital equipment. Mr. Tyson holds a B.S. in
physics, an M.S. in political science and an M.S. in nuclear engineering, all
from the Massachusetts Institute of Technology. Mr. Tyson is a member of the
board of directors of the Semiconductor Industry Suppliers of North America
(formerly SEMI-SEMATECH, Inc.). In addition, Mr. Tyson is a member of the North
American Advisory Board of SEMI, a trade association that represents the
worldwide semiconductor equipment industry.

         STEPHEN D. ALLISON joined us in 1997 and served as our Chief
Financial Officer until January 28, 2000. Mr. Allison was Vice President and
Chief Financial Officer of Helix Technology Corporation, a manufacturer of
cryogenic vacuum systems, from 1995 to 1997. Mr. Allison also served as Vice
President, Finance of Behring Diagnostic Systems, Inc., a supplier of
immunoassay test and analysis systems, from 1991 to 1995, served as Vice
President, Planning of Bay State Health Care, Inc., from 1989 to 1991 and
worked at Teradyne, Inc. in various financial positions from 1974 to 1989.
Mr. Allison holds a B.A. in economics from Columbia Univeristy and an M.B.A
from the Amos Tuck School of Business Administration at Dartmouth College,
and is a Certified Public Accountant.

         ROBERT G. POSTLE was named our Vice President, General Manager, Factory
Systems Division in September 1999. Mr. Postle joined PRI in 1994 as Vice
President, Marketing and Sales, became Vice President, Marketing, Sales and
Service in 1997 and was named Vice President, Sales, Service and Field
Operations in 1998. From 1989 to 1994, Mr. Postle was Vice President of
Marketing and Sales at ULVAC Technologies, Inc., a manufacturer of vacuum
technology products. From 1987 to 1989, Mr. Postle was Vice President of
Marketing and Sales at ASM Ion Implant, Inc., a manufacturer of ion implantation
equipment. Mr. Postle holds a B.S. in business administration from the State
University of New York, Brockport.

         EDWARD A. WAGNER was appointed our Vice President, General Manager, OEM
Systems Division in January 1999. Mr. Wagner joined PRI as Vice President, Sales
in 1997. From 1989 to 1997, Mr. Wagner was Vice President of US operations for
Metron Technology, a worldwide sales and distribution company supporting many of
the major semiconductor equipment manufacturers in both the US and Japan. From
1979 to 1989, he served as President and General Manager of BGL Corp., a
manufacturer of OEM automation products and quartz glass products. Mr. Wagner
holds a B.S. from the University of California at Berkeley and an M.B.A. from
Golden Gate University, San Francisco.

<PAGE>


         AMRAM RASIEL has been a director of PRI since 1982. Dr. Rasiel is a
private investor. He is a director of Progress Software Corporation, a provider
of application development software, and of a number of privately held
companies.

         BORUCH B. FRUSZTAJER became a director of PRI in 1982. Mr. Frusztajer
has been the President of BBF Corporation, an industrial management company,
since 1984.

         ALEXANDER V. D'ARBELOFF became a director of PRI in 1982. Mr.
d'Arbeloff has been Chairman of the Board of Teradyne, Inc., a publicly-held
manufacturer of automatic testing equipment used in the manufacture of
semiconductors, since 1977. From 1971 to 1996, Mr. d'Arbeloff served as
President of Teradyne, and also served as its Chief Executive Officer from 1971
to 1997. He is Chairman of the Corporation of the Massachusetts Institute of
Technology. Mr. d'Arbeloff is a director of a number of privately held
companies.

         KENNETH  M.  THOMPSON  became  a  director  of  PRI in  July 1998.
Mr. Thompson was employed by Intel Corporation for twenty-five years, most
recently as Vice President, Technology Manufacturing Engineering. He retired
from Intel in 1998. Mr. Thompson is a director of LAM Research Corp., Silicon
Valley Group, Inc. and Gasonics Corporation.

ITEM 11.  EXECUTIVE COMPENSATION

         The following table provides certain summary information concerning
the compensation earned by PRI's Chief Executive Officer and each of the four
other most highly compensated executive officers, as well as a former officer
(collectively, the "Named Executive Officers"), for services rendered in all
capacities to PRI during fiscal 1999 and during the fiscal years ended
September 30, 1997 and 1998 ("fiscal 1997" and "fiscal 1998," respectively).

                           SUMMARY COMPENSATION TABLE


<TABLE>
<CAPTION>

                      NAME AND                FISCAL      SALARY($)       BONUS($)        SECURITIES         ALL OTHER
                 PRINCIPAL POSITION            YEAR       ---------       --------        UNDERLYING        COMPENSATION
                 ------------------           ------                                      OPTIONS(#)           ($)(2)
                                                                                          ----------           ------
                                                           ANNUAL COMPENSATION(1)           AWARDS
                                                           ----------------------         LONG-TERM
                                                                                         COMPENSATION
                                                                                         ------------

<S>                                               <C>         <C>         <C>            <C>                <C>

Mordechai Wiesler                                 1999        $201,539              *             40,000            $12,360
  Chairman of the Board                           1998        $257,212              *             30,000            $10,485
                                                  1997        $243,077       $187,500             40,000            $11,500
Mitchell G. Tyson                                 1999        $266,010              *             55,000             $5,412
  President and Chief Executive Officer           1998        $247,289              *            130,000             $5,363
                                                  1997        $218,077       $168,750             40,000             $5,260
Robert G. Postle                                  1999        $207,038              *             61,000             $5,412
  Vice President, General Manager, Factory        1998        $196,789              *             25,500             $5,667
  Systems Division                                1997        $155,847       $100,000             25,000             $5,180
Stephen D. Allison(3)                             1999        $202,596              *             26,000             $3,754
  Chief Financial Officer                         1998        $194,789              *             47,000             $2,936
                                                  1997         $84,135        $35,096             30,000             $1,512

</TABLE>


<PAGE>

<TABLE>

<S>                                               <C>         <C>         <C>            <C>                <C>

Edward A. Wagner(4)                               1999        $204,346              *             39,000             $6,528
  Vice President, General Manager,                1998        $164,237              *             45,500             $5,362
  OEM Systems Division                            1997         $34,303        $52,000             22,500               $518
Robert Klimm (3)                                  1999        $229,260              -             39,000             $6,157
   Former Vice President, General                 1998        $216,231              -             18,000             $7,106
   Manager, Factory Systems Division              1997        $100,010        $52,055             40,000             $1,764

</TABLE>

-----------
(1)      In accordance with the rules of the Securities and Exchange Commission,
         other compensation in the form of perquisites and other personal
         benefits has been omitted because such perquisites and other personal
         benefits constituted less than $50,000 and less than ten percent of the
         total annual salary and bonus for each executive officer.
(2)      The amounts reported include PRI's contributions to the PRI Savings and
         Retirement Plan during fiscal 1999, fiscal 1998 and fiscal 1997,
         respectively, for the benefit of Mr. Wiesler ($4,800, $4,185 and
         $5,200), Mr. Tyson ($4,800, $4,904 and $4,973), Mr. Postle ($4,800,
         $5,310 and $3,629), Mr. Allison ($2,026, $1,928 and $1,410) and Mr.
         Klimm ($4,800, $6,427 and $1,615) and during fiscal 1999 and fiscal
         1998 for Mr. Wagner ($4,800 and $4,927); and premiums paid by PRI on
         excess life insurance policies during fiscal 1999, fiscal 1998 and
         fiscal 1997, respectively, for Mr. Wiesler ($7,560, $6,300 and $6,300),
         Mr. Tyson ($612, $459 and $510), Mr. Postle ($612, $357 and $505), Mr.
         Allison ($1,728, $1,008 and $102) and Mr. Klimm ($1,357, $679 and $149)
         and during fiscal 1999 and fiscal 1998 for Mr. Wagner ($1,728 and
         $435).
(3)      Messrs. Allison and Klimm joined PRI during fiscal 1997 and, therefore,
         received  compensation for only a portion of that fiscal year.
(4)      Mr. Wagner joined PRI as Vice President, Sales in June 1997 and,
         therefore, received compensation for only a portion of that fiscal
         year. He became Vice President, General Manager, OEM Systems Division
         in March 1999.

OPTION GRANTS IN LAST FISCAL YEAR

         The following table contains information concerning stock option grants
made during fiscal 1999 under the 1994 Stock Option Plan and the 1997 Stock
Option Plan to the Chief Executive Officer and each of the other Named Executive
Officers:

                        OPTION GRANTS IN LAST FISCAL YEAR

<TABLE>
<CAPTION>
NAME                           OPTIONS          % OF TOTAL        EXERCISE OR        EXPIRATION        5%($)       10% ($)
---                                                                                                    -----       -------
                             GRANTED(#)          OPTIONS          BASE PRICE            DATE
                             ----------                                                 ----
                                                GRANTED TO       ($/SHARE)(1)
                                               EMPLOYEES IN      ------------
                                               FISCAL YEAR
                                               -----------
                                                                                                      POTENTIAL REALIZABLE
                                                                                                        VALUE AT ASSUMED
                                                                                                     ANNUAL RATES OF STOCK
                                                                                                     PRICE APPRECIATION FOR
                                                                                                         OPTION TERM(2)
                                                                                                         --------------
<S>                               <C>                  <C>          <C>                 <C>               <C>         <C>
Mordechai Wiesler                 30,000(3)            1.8          $27.375             3/03/05           $279,304    $633,644
                                  10,000(4)            0.6          $23.3125            5/11/05            $79,285    $179,870
Mitchell G. Tyson                 40,000(3)            2.4          $27.375             3/03/05           $372,405    $844,859
                                  15,000(4)            0.9          $23.3125            5/11/05           $118,927    $269,805

</TABLE>

<PAGE>

<TABLE>
<S>                               <C>                  <C>          <C>                 <C>               <C>         <C>
Robert G. Postle                  27,000(3)            1.6          $27.375             3/03/05           $251,373    $570,280
                                   9,000(4)            0.5          $23.3125            5/11/05            $71,356    $161,883
                                  25,000(5)            1.5          $28.625             8/31/05           $243,381    $552,148
Stephen D. Allison                20,000(3)            1.2          $27.375             3/03/05           $186,202    $422,430
                                   6,000(4)            0.4          $23.3125            5/11/05            $47,571    $107,922
Edward A. Wagner                  30,000(6)            1.8          $27.00              1/04/05           $275,477    $624,964
                                   9,000(4)            0.5          $23.3125            5/11/05            $71,356    $161,883
Robert Klimm                      30,000(3)            1.8          $27.375             3/03/05           $279,304    $633,644
                                   9,000(4)            0.5          $23.3125            5/11/05            $71,356    $161,883

</TABLE>


-----------
(1)      All options were granted at exercise prices not less than fair market
         value, which was determined by the board of directors to be the last
         sale price of the common stock on the date of grant as reported by the
         Nasdaq Stock Market.
(2)      Amounts reported in this column represent hypothetical values that may
         be realized upon exercise of the options immediately prior to the
         expiration of their term, assuming the specified compounded rates of
         appreciation of the common stock over the term of the options. These
         numbers are calculated based on rules promulgated by the Securities and
         Exchange Commission and do not represent PRI's estimate of future stock
         price growth. Actual gains, if any, on stock option exercises and
         common stock holdings are dependent on the timing of such exercises and
         the future performance of the common stock. There can be no assurance
         that the rates of appreciation assumed in this table can be achieved or
         that the amounts reflected will be received by the Named Executive
         Officers. This table does not take into account any appreciation in
         price of the common stock from the date of grant to the current date.
         The values shown are net of the option price, but do not include
         deductions for taxes or other expenses associated with the exercise.
(3)      Option vests in twenty equal quarterly installments beginning June 30,
         1999 and ending March 3, 2004.
(4)      Fully vested on December 5, 1999.
(5)      Option issued in connection with Mr. Postle's promotion to the position
         of Vice President, General Manager, Factory Systems Division. Option
         vests in twenty equal quarterly installments beginning November 30,
         1999 and ending August 31, 2004.
(6)      Option issued in connection with Mr. Wagner's promotion to the position
         of Vice President, General Manager, OEM Systems Division. Option vests
         in twenty equal quarterly installments beginning April 4, 1999 and
         ending January 4, 2004.

OPTION/SAR EXERCISES AND FISCAL YEAR-END VALUES

         The following table sets forth information concerning option exercises
and holdings under PRI's 1984 Incentive Stock Option Plan, 1994 Incentive and
Nonqualified Stock Option Plan and 1997 Non-Incentive Stock Option Plan as of
September 30, 1999 with respect to the Chief Executive Officer and the other
Named Executive Officers:


<PAGE>
                          FISCAL YEAR-END OPTION VALUES

<TABLE>
<CAPTION>

                                                                      COMMON STOCK
                                                                       UNDERLYING                   VALUE OF UNEXERCISED
                                                                 UNEXERCISED OPTIONS AT            IN-THE-MONEY OPTIONS AT
                                                                   FISCAL YEAR-END (#)              FISCAL YEAR-END $(2)
                                                                   -------------------              --------------------
                                SHARES
                                ACQUIRED         VALUE
                                  ON           REALIZED
NAME                           EXERCISE(#)       ($)(1)       EXERCISABLE     UNEXERCISABLE     EXERCISABLE     UNEXERCISABLE
----                          -----------       -------       -----------     -------------     -----------     -------------
<S>                              <C>        <C>                 <C>               <C>         <C>               <C>
Mordechai Wiesler                75,000     $1,820,473          77,051            86,349      $1,757,298        $1,383,078

Mitchell G. Tyson                95,000     $2,369,375         157,951           182,469      $4,153,149        $3,561,915

Robert G. Postle                 32,420       $476,868           7,187            90,951        $190,320        $1,186,378

Stephen D. Allison                    *              *          15,401            57,599        $320,821          $952,554

Edward A. Wagner                  9,501       $176,572           3,000            61,999         $74,250          $917,416

Robert Klimm                     27,400       $418,381           2,000            67,600         $49,500          $855,138

</TABLE>

-----------
(1)      Amounts disclosed in this column do not necessarily reflect amounts
         received by the Named Executive Officers but are calculated based on
         the difference between the fair market value of the common stock on the
         date of exercise and the exercise price of the options. Named Executive
         Officers will receive cash only if and when they sell the common stock
         issued upon exercise of the options, and the amount of cash received by
         such individuals is dependent on the price of the common stock at the
         time of such sale.
(2)      Calculated on the basis of the last sale price of the common stock on
         September 30, 1999 as reported by the Nasdaq Stock Market ($36.125 per
         share), less the applicable option exercise price.

RETENTION AND SEVERANCE AGREEMENTS

         PRI has entered into retention agreements with each of Messrs. Wiesler,
Tyson, Postle, Allison and Wagner. The terms of each agreement were amended in
fiscal 1999. The agreements provide for certain payments upon the occurrence of
certain events following a "change of control" of PRI. A "change of control" is
defined in each agreement to mean (i) any person becoming the beneficial owner
of securities of PRI representing fifty percent (50%) or more of the total
voting power; (ii) a change in the composition of the board of directors
creating a majority of directors consisting of individuals other than directors
of PRI as of the date of the retention agreement or their designated successors;
or (iii) the merger or consolidation of PRI with any other corporation (other
than a merger or consolidation keeping at least fifty percent (50%) of the total
voting power in the hands of PRI stockholders) or PRI's liquidation or the sale
or disposition by PRI of all or substantially all of its assets.

         Each agreement provides that PRI will pay certain severance benefits to
the executive officer in the event that, within 12 months after a change of
control, the executive's employment is terminated other than for cause, as
defined in the agreement, or if the executive resigns after the occurrence of
one or more certain events, such as material reduction in responsibilities or
salary or relocation to a facility in a different location without the
executive's consent.

         Each agreement provides that, if the executive is terminated or resigns
within 12 months after a change of control under circumstances that would
entitle the executive to severance benefits, then PRI will be obligated to pay
to the executive, in a single payment, an amount equal to the sum of (a) his
then-current annual base compensation, (b) the bonus (if any) that PRI (or its
successor) paid the executive with respect to its fiscal year most recently

<PAGE>


ended before such termination or resignation and (c) a prorated fraction of
the amount of his "target bonus" for the fiscal year of PRI in which the
termination or resignation occurs. Each agreement further provides that, upon
such termination or resignation, or upon the first anniversary of a change of
control if no such termination or resignation occurs, 100% of the otherwise
unvested portion of each stock option held by the executive will become fully
exercisable, and 100% of each option held by PRI to repurchase stock of PRI
owned by the executive will terminate.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

         No member of the Compensation Committee is a former or current employee
of PRI or a party to any other relationship of a character required to be
disclosed pursuant to Item 402(j) of Regulation S-K.

COMPENSATION COMMITTEE REPORT ON EXECUTIVE COMPENSATION

         This report has been furnished by the Compensation Committee. Boruch B.
Frusztajer and Alexander V. d'Arbeloff, two non-employee members of the Board of
Directors, are the members of the Committee. The Committee meets at least
annually or more frequently if requested by the Board of Directors. The
Committee is primarily responsible for the review of executive compensation,
which includes base salary, profit sharing, and stock option awards.

 COMPENSATION POLICIES. PRI believes that it is critical to its continued
success to attract and retain highly qualified executive officers who will play
a vital role in future achievements. To this end, PRI has established its
compensation policy to reward executives based upon corporate, departmental and
individual performance which is measured against the internal goals set for each
area. PRI also understands the need to provide long term incentives to its
executive officers to achieve future financial and strategic goals which include
PRI's growth, enhancement of PRI's profitability and thus shareholder value. PRI
believes that its total compensation is sufficiently competitive to retain and,
if necessary, attract executive officers capable of leading PRI in accomplishing
its business goals.

         Executive compensation for fiscal 1999 consisted of a base salary and
equity-based long-term incentive compensation in the form of incentive and
nonstatutory stock options. Since options granted under the 1994 Stock Option
Plan and 1997 Stock Option Plan generally vest over a five-year period, option
awards encourage the holders to improve the profitability and shareholder value
of PRI. Also, to reward performance PRI provides executives with additional cash
compensation in the form of profit sharing bonuses. However, no bonus
compensation was awarded in fiscal 1999.

 BASE SALARIES AND CHIEF EXECUTIVE OFFICER COMPENSATION. The salaries of the
executive officers are established annually by evaluating requirements of the
position, the contribution of the individual executive with respect to PRI's
performance and the executive's responsibility, technical experience and future
potential. Base salaries of the executive officers are generally adjusted
annually in January to reflect comparable executive salaries for comparably
sized companies and to maintain the objectives of the compensation policy noted
above. In determining base salaries, the Compensation Committee relies upon
independent surveys of companies in the industry to determine whether PRI's
executive compensation is in a competitive range for executives within PRI's
industry. The salary of Mitch Tyson, PRI's Chief Executive Officer, was $266,010
for fiscal 1999. This represented an increase of approximately 7.6% from fiscal
1998.


<PAGE>


 LONG-TERM INCENTIVE COMPENSATION. One of PRI's goals is the enhancement of
shareholder value. The principal incentive tool used to achieve this goal is the
periodic award to key employees of options to purchase common stock. PRI's stock
option plans are long-term plans designed to link executive rewards to
shareholder value over time. Stock options granted typically have a term of six
(6) years and vest in twenty quarterly installments over a period of five (5)
years from the date of grant. In fiscal 1999, PRI granted long-term incentive
compensation in the form of incentive and nonstatutory stock options under the
1994 Stock Option Plan and 1997 Stock Option Plan to PRI's executive officers.
These grants included options granted to Messrs. Wiesler, Tyson, Postle, Allison
and Wagner to purchase up to 40,000, 55,000, 61,000, 26,000 and 39,000 shares of
common stock, respectively. See "Option Grants in Last Fiscal Year."

Boruch B. Frusztajer
Alexander V. d'Arbeloff

                                PERFORMANCE GRAPH

         The following performance graph compares the performance of PRI's
cumulative stockholder return with that of a broad market index, the Nasdaq
Stock Market Index for U.S. Companies, and a published industry index, the
Hambrecht & Quist Semiconductor Sector Index. The cumulative stockholder returns
for shares of common stock and for the market and industry indices are
calculated assuming that $100 was invested on October 13, 1994, the date on
which the common stock commenced trading on the National Market System of the
Nasdaq Stock Market. PRI paid no cash dividends during the periods shown. The
performance of the market and industry indices is shown on a total return
(dividends reinvested) basis, calculated monthly as of the last day of month
indicated.

                  PRI AUTOMATION INC. CUMULATIVE TOTAL RETURNS



<TABLE>
<CAPTION>

     DATES           PRI AUTOMATION        NASDAQ STOCK                H&Q
                                            MARKET -U.S.       SEMICONDUCTOR SECTOR


       <S>           <C>                    <C>                <C>

       10/13/94          100.00                   100.00                    100.00
         Oct-94          112.96                   101.45                    109.51
         Nov-94          124.07                    98.09                    106.94
         Dec-94          119.44                    98.36                    106.95
         Jan-95          118.52                    98.92                    108.71
         Feb-95          133.33                   104.15                    122.14
         Mar-95          164.81                   107.24                    129.15
         Apr-95          194.44                   110.62                    147.43
         May-95          209.26                   113.47                    159.60
         Jun-95          242.59                   122.67                    181.26
         Jul-95          303.70                   131.69                    206.77
         Aug-95          279.63                   134.36                    202.91
         Sep-95          303.70                   137.44                    204.85
         Oct-95          274.07                   136.65                    192.49
         Nov-95          303.70                   139.86                    170.34

</TABLE>


<PAGE>


<TABLE>


       <S>           <C>                    <C>                <C>

         Dec-95          260.19                   139.12                    148.84
         Jan-96          211.11                   139.80                    146.82
         Feb-96          176.85                   145.12                    147.57
         Mar-96          181.48                   145.60                    140.57
         Apr-96          209.26                   157.67                    161.05
         May-96          295.37                   164.91                    156.06
         Jun-96          225.93                   157.48                    134.72
         Jul-96          194.44                   143.44                    119.60
         Aug-96          216.67                   151.47                    130.90
         Sep-96          242.59                   163.06                    152.94
         Oct-96          262.96                   161.26                    154.35
         Nov-96          353.70                   171.23                    194.51
         Dec-96          337.04                   171.07                    192.76
         Jan-97          445.37                   183.23                    232.40
         Feb-97          365.74                   173.09                    221.25
         Mar-97          353.70                   161.79                    216.65
         Apr-97          379.63                   166.85                    235.23
         May-97          564.81                   185.76                    254.01
         Jun-97          562.03                   191.45                    244.32
         Jul-97          735.19                   211.66                    298.83
         Aug-97          792.59                   211.33                    304.50
         Sep-97          866.67                   223.82                    305.41
         Oct-97          566.67                   212.24                    239.09
         Nov-97          505.56                   213.30                    230.66
         Dec-97          427.78                   209.88                    203.29
         Jan-98          407.41                   216.47                    227.08
         Feb-98          515.27                   236.78                    249.46
         Mar-98          387.96                   245.51                    233.09
         Apr-98          396.30                   249.67                    253.54
         May-98          300.46                   235.97                    208.36
         Jun-98          252.78                   252.61                    200.26
         Jul-98          206.48                   249.85                    206.50
         Aug-98          185.19                   200.98                    157.84
         Sep-98          185.19                   228.68                    174.59
         Oct-98          256.48                   237.70                    218.59
         Nov-98          355.56                   261.74                    248.55
         Dec-98          385.19                   295.70                    285.36
         Jan-99          525.93                   338.70                    356.23
         Feb-99          444.44                   308.34                    301.35
         Mar-99          311.11                   330.76                    323.69
         Apr-99          367.59                   340.05                    329.58
         May-99          362.96                   332.23                    340.43
         Jun-99          537.04                   361.89                    424.50
         Jul-99          458.33                   356.63                    441.69
         Aug-99          424.07                   370.76                    476.31
         Sep-99          535.19                   370.19                    476.33

</TABLE>


<PAGE>


ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

         The following table sets forth certain information with respect to
the beneficial ownership of our common stock as of January 10, 2000 by (i)
each person or entity known to us to own beneficially five percent or more of
PRI's common stock, (ii) each of our directors, (iii) the Chief Executive
Officer and the other Named Executive Officers and (iv) the executive
officers and directors as a group:

<TABLE>
<CAPTION>

                                                                 SHARES BENEFICIALLY
                                                                   OWNED(1)(2)
                                                                   -----------
NAME AND ADDRESS(3)                                              NUMBER      PERCENT
-------------------                                              ------      -------
<S>                                                          <C>              <C>

FMR Corp.(4)
82 Devonshire Street,
Boston, MA 02109                                                  1,996,940     8.8%
Mordechai Wiesler(5)                                                832,710     3.6%
Dr. Amram Rasiel(6)                                                 574,710     2.5%
Mitchell G. Tyson(7)                                                307,648     1.3%
Boruch B. Frusztajer(8)                                             105,512        *
Alexander V. d'Arbeloff(9)                                           86,764        *
Robert G. Postle(10)                                                  7,680        *
Stephen D. Allison(11)                                                8,184        *
Kenneth M. Thompson(12)                                              20,000        *
Edward A. Wagner(13)                                                  4,975        *
Robert Klimm                                                             --       --
All directors and executive officers as a group (9                1,948,183     8.4%
  persons)(14)

</TABLE>


-----------
*        Less than one percent.
(1)      Beneficial ownership is determined in accordance with the rules of the
         Securities and Exchange Commission. The persons named in this table
         have sole voting and investment power with respect to all shares of
         common stock shown as beneficially owned by them, subject to community
         property laws where applicable and subject to the information contained
         in the footnotes to this table. Shares of common stock subject to
         options currently exercisable or exercisable within 60 days following
         the date of this table are deemed outstanding for computing the share
         ownership and percentage of the person holding such options, but are
         not deemed outstanding for computing the percentage of any other
         person.
(2)      The number of shares of common stock deemed  outstanding as of the date
         of this table,  January 10,  2000, is 22,761,449.
(3)      Unless otherwise noted,  address is in care of PRI  Automation, Inc.,
         805 Middlesex Turnpike,  Billerica, Massachusetts 01821-3986.
(4)      Information is based on a Schedule 13G filed by FMR Corp. with the
         Securities and Exchange Commission on January 7, 1999. The Schedule 13G
         states that Fidelity Management & Research Company, a wholly-owned
         subsidiary of FMR Corp. and an investment adviser registered under
         Section 203 of the Investment Advisers Act of 1940, is the beneficial
         owner of 1,690,440 shares as a result of acting as investment adviser
         to various investment companies, that Fidelity Management Trust
         Company, a wholly-owned subsidiary of FMR Corp. and a bank as defined
         in Section 3(a)(6) of the Securities Exchange Act of 1934, is the
         beneficial owner of 297,000 shares as a result of its serving as
         investment manager of institutional accounts and that Fidelity
         International Limited is the beneficial owner of 9,500 shares. The
         Schedule 13G states

<PAGE>


         that various persons have the right to receive, or to direct the
         receipt of dividends from, or the proceeds from the sale of, the common
         stock, and that no one person's interest in the common stock is more
         than five percent.

(5)      Includes 72,390 shares  issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table.

(6)      Includes 22,000 shares  issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table.

(7)      Includes 197,011 shares issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table and 8,100
         shares held by members of Mr. Tyson's family.

(8)      Includes 22,000 shares issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table and 58,762
         shares held by members of Mr. Frusztajer's family.

(9)      Includes 22,000 shares  issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table.

(10)     Includes 7,633 shares  issuable upon the exercise of  outstanding
         options exercisable within 60 days of the date of this table.

(11)     Includes 7,680 shares  issuable upon the exercise of  outstanding
         options exercisable within 60 days of the date of this table.

(12)     Includes 20,000 shares  issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table.

(13)     Includes 4,975 shares  issuable upon the exercise of  outstanding
         options exercisable within 60 days of the date of this table.

(14)     Includes 375,689 shares issuable upon the exercise of outstanding
         options exercisable within 60 days of the date of this table. See notes
         5 through 13.

ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

         In August 1998, PRI entered into a loan arrangement with Robert Postle,
then our Vice President, Sales, Service and Field Operations and now our Vice
President, General Manager, Factory Systems Division. PRI loaned Mr. Postle
$150,000 pursuant to a three-year promissory note with interest accruing at 6%.
The note was secured by a mortgage on Mr. Postle's residence. The outstanding
principal under the note, together with accrued interest thereon, was due and
payable at the maturity date or upon the earlier termination of Mr. Postle's
employment either by PRI for cause or voluntarily by Mr. Postle. This note,
together with all accrued interest, was repaid in full in January 2000.


<PAGE>


                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934 (the "Exchange Act"), the Registrant has duly caused this
amendment to be signed on its behalf by the undersigned, thereunto duly
authorized.

                                       PRI AUTOMATION, INC.

Date: January 28, 2000                 By: /s/ Mitchell G. Tyson
                                           -----------------------------------
                                             Mitchell G. Tyson
                                             Chief Executive Officer