UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 02549

                                   FORM 10-K/A

                          Amendment No. 1 to Form 10-K

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

                  For the fiscal year ended: December 31, 2002

                                       OR

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

                  For the transition period from _____ to _____

                         Commission File Number: 1-7211

                              IONICS, INCORPORATED
             (Exact name of registrant as specified in its charter)

          Massachusetts                                  04-2068530
    (State of incorporation)                (IRS Employer Identification Number)

         65 Grove Street                                 02472-2882
      Watertown, Massachusetts                           (Zip Code)
(Address of principal executive offices)

        Registrant's telephone number, including area code: (617)926-2500

                 Securities registered pursuant to Section 12(b)
                   of the Act: Common Stock, $1.00 par value

       Name of each exchange on which registered: New York Stock Exchange

        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]

Indicate  by check mark  whether  the  registrant  is an  accelerated  filer (as
defined in Rule 12b-2 of the Act).
                                   Yes X    No ___

The  aggregate  market  value  of the  Common  Stock of the  registrant  held by
non-affiliates as of June 28, 2002 was $415,244,560 (17,123,487 shares at $24.25
per  share)  (includes  shares  owned by a trust for the  indirect  benefit of a
non-employee  director, and by a trust for the indirect benefit of a spouse of a
non-employee director).

As of March 21, 2003,  17,555,046 shares of Common Stock,  $1.00 par value, were
issued and outstanding.

                       DOCUMENTS INCORPORATED BY REFERENCE

The  Registrant  intends  to  file a  definitive  proxy  statement  pursuant  to
Regulation  14A within 120 days of the end of the fiscal year ended December 31,
2002. Portions of such proxy statement are incorporated by reference into Item 5
and Part III of this Annual Report on Form 10-K.

<PAGE>

                                EXPLANATORY NOTE

Ionics, Incorporated (the Company) is filing this Amendment No. 1 to Form 10-K
to amend its Annual Report on Form 10-K for the year ended December 31, 2002 to
correct an inadvertent typographical error in Item 14, "Controls and
Procedures."

The Company hereby amends the following item:

1.       Item 14 of Part III is amended so that the first three words of the
         last paragraph of Item 14 shall read, "In March 2003". A copy of the
         corrected and amended Item 14 follows:



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<PAGE>
ITEM 14.      CONTROLS AND PROCEDURES

As part of the Company's continuing efforts to ensure that information required
to be disclosed by the Company in its Securities and Exchange Commission filings
is appropriately accumulated and disseminated to allow timely decisions
regarding required disclosure, the Company has been taking various actions to
strengthen its system of internal controls and disclosure controls and
procedures. Such actions were also taken to enhance the processes by which the
Company manages its various divisions and subsidiaries, because managing a large
number of relatively small, locally managed businesses around the world presents
significant challenges.

Prior to the evaluation of the Company's disclosure controls and procedures made
in connection with the filing of its Quarterly Report on Form 10-Q for the
periods ended September 30, 2002, the Company made changes in its internal
controls and took other actions designed to enhance the Company's internal
controls, which consisted of the following:

o    the hiring of new personnel including, two new segment controllers in April
     and July of 2002, three new divisional controllers in May and September of
     2002, a corporate director of accounting in July 2002, and a new
     consolidation accountant in September 2002, to enhance the quality of its
     accounting capabilities;
o    the replacement of the senior operating executive at the Company's French
     subsidiary and the reassignment of much of the operational responsibility
     for that subsidiary to the Company's Italian subsidiary;
o    the implementation of a new financial consolidation software package (which
     became operational in September 2002);
o    the implementation of a centralized bid and proposal review and approval
     process at the beginning of 2002;
o    the expansion of the internal audit function through the use of outside
     resources beginning in March 2002;
o    the formalization of certain accounting and information technology policies
     and procedures at various times throughout the year;
o    the hiring of a Director of Project Management in October 2002 to oversee
     project-related procedures and to train project managers at locations to
     enable them to better comply with Company goals, policies and procedures;
     and
o    the institution of procedures requiring written quarterly certifications
     and representations from the head of each business group and the local
     controller of each business location.

Since that evaluation in November 2002, the Company has made additional changes
in its internal controls and taken other actions designed to enhance the
Company's internal controls, which consisted of the following:

o    the formation of a disclosure committee to oversee the effectiveness of the
     Company's disclosure controls and procedures;
o    in furtherance of the centralized bid and proposal review and approval
     process, the establishment of formal, systematic procedures for reviewing
     all major commercial projects being undertaken by the Company, including
     monthly participation by senior management;
o    the finalization of a project database to facilitate the tracking and
     analysis of project performance throughout the Company in December 2002;
o    the hiring of a senior financial manager into a newly created position as
     European Controller in December 2002, who is responsible for providing
     financial oversight and control for the Equipment Business Group's European
     operations; and
o    the conduct of a conference, and other educational activities, for the
     Company's segment and divisional controllers and corporate accounting
     staff, which included programs regarding, among other topics, inter-company
     transactions, key policies under U.S. generally accepted accounting
     principles (e.g., SAB 101, SOP 81-1), the Sarbanes-Oxley Act of 2002,
     internal controls, U.S. regulation of international transactions, and key
     responsibilities of the local controllers.

In connection with the audit of its financial statements for 2002, the Company
was advised by its independent auditor that certain of its internal controls had
deficiencies and material control weaknesses. Consequently, and with the goal of
further improving the quality and timeliness of the information available to
management, the Company is continuing to implement measures designed to address
those deficiencies and weaknesses as follows:

o    to evaluate and strengthen its financial and accounting staff and their
     knowledge and understanding of key policies under U.S. generally accepted
     accounting principles and of their responsibilities;
o    to improve monitoring controls to assure the prevention or detection of
     material accounting errors on a timely basis;
o    to reduce the time necessary to collect and report financial and operating
     data by improving the timing and accuracy of forecasting and emphasizing
     more frequent reviews of the Company's balance sheets and reconciliation of
     intercompany balances;
o    to continue to update its accounting policies and procedures.

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<PAGE>

In March 2003, the Company carried out an evaluation, under the supervision and
with the participation of the Company's management, including the Company's
Chief Executive Officer and Chief Financial Officer, of the effectiveness of the
Company's "disclosure controls and procedures." The SEC defines "disclosure
controls and procedures" as a company's controls and other procedures that are
designed to ensure that information required to be disclosed by the company in
the reports it files or submits under the Securities Exchange Act of 1934 is
recorded, processed, summarized and reported, within the time periods specified
in the SEC's rules and forms. Based on their evaluation of the Company's
disclosure controls and procedures, the Company's Chief Executive Officer
(principal executive officer) and Chief Financial Officer (principal financial
officer) concluded that the Company's disclosure controls and procedures were
substantially effective for these purposes as of the date of the evaluation.

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<PAGE>

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this amendment to be signed on its behalf by the
undersigned, thereunto duly authorized.

                              IONICS, INCORPORATED
                                  (Registrant)


Date: April 1, 2003           By: /s/ Stephen Korn
                                  ----------------
                                  Stephen Korn
                                  Vice President and
                                  General Counsel



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<PAGE>



                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER


I, Arthur L. Goldstein, certify that:

1.   I have reviewed this Amendment No. 1 to annual report on Form 10-K of
     Ionics, Incorporated;

2.   Based on my knowledge, this Amendment No. 1 to annual report does not
     contain any untrue statement of a material fact or omit to state a material
     fact necessary to make the statements made, in light of the circumstances
     under which such statements were made, not misleading with respect to the
     period covered by this annual report;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this Amendment No. 1 to annual report, fairly
     present in all material respects the financial condition, results of
     operations and cash flows of the registrant as of, and for, the periods in
     this annual report;

4.   The registrant's other certifying officer and I are responsible for
     establishing and maintaining disclosure controls and procedures (as defined
     in Exchange Act Rules 13a-14 and 15d-14) for the registrant and have:

     a)   designed  such  disclosure  controls  and  procedures  to ensure  that
          material  information  relating  to  the  registrant,   including  its
          consolidated subsidiaries,  is made known to us by others within those
          entities,  particularly  during the period in which this annual report
          is being prepared;

     b)   evaluated the  effectiveness of the registrant's  disclosure  controls
          and procedures as of a date within 90 days prior to the filing date of
          this annual report (the "Evaluation Date"); and

     c)   presented   in  this   annual   report  our   conclusions   about  the
          effectiveness  of the disclosure  controls and procedures based on our
          evaluation as of the Evaluation Date;

5.   The registrant's other certifying officer and I have disclosed, based on
     our most recent evaluation, to the registrant's auditors and the audit
     committee of registrant's board of directors (or persons performing the
     equivalent functions):

     a)   all  significant  deficiencies  in the design or operation of internal
          controls  which could  adversely  affect the  registrant's  ability to
          record,  process,   summarize  and  report  financial  data  and  have
          identified for the  registrant's  auditors any material  weaknesses in
          internal controls; and

     b)   any fraud, whether or not material,  that involves management or other
          employees who have a  significant  role in the  registrant's  internal
          controls, and

6.   The registrant's other certifying officer and I have indicated in this
     Amendment No. 1 to annual report whether there were significant changes in
     internal controls or in other factors that could significantly affect
     internal controls subsequent to the date of our most recent evaluation,
     including any corrective actions with regard to significant deficiencies
     and material weaknesses.

                                   /s/Arthur L. Goldstein
                                   ----------------------
                                     Arthur L. Goldstein
                                     Chairman and
                                     Chief Executive Officer
                                     April 1, 2003

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<PAGE>


                    CERTIFICATION OF CHIEF FINANCIAL OFFICER


I, Daniel M. Kuzmak, certify that:

1.   I have reviewed this Amendment No. 1 to annual report on Form 10-K of
     Ionics, Incorporated;

2.   Based on my knowledge, this Amendment No. 1 to annual report does not
     contain any untrue statement of a material fact or omit to state a material
     fact necessary to make the statements made, in light of the circumstances
     under which such statements were made, not misleading with respect to the
     period covered by this annual report;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this Amendment No. 1 to annual report, fairly
     present in all material respects the financial condition, results of
     operations and cash flows of the registrant as of, and for, the periods in
     this annual report;

4.   The registrant's other certifying officer and I are responsible for
     establishing and maintaining disclosure controls and procedures (as defined
     in Exchange Act Rules 13a-14 and 15d-14) for the registrant and have:

a)   designed such disclosure controls and procedures to ensure that material
     information relating to the registrant, including its consolidated
     subsidiaries, is made known to us by others within those entities,
     particularly during the period in which this annual report is being
     prepared;

b)   evaluated the effectiveness of the registrant's disclosure controls and
     procedures as of a date within 90 days prior to the filing date of this
     annual report (the "Evaluation Date"); and

c)   presented in this annual report our conclusions about the effectiveness of
     the disclosure controls and procedures based on our evaluation as of the
     Evaluation Date;

5.   The registrant's other certifying officer and I have disclosed, based on
     our most recent evaluation, to the registrant's auditors and the audit
     committee of registrant's board of directors (or persons performing the
     equivalent functions):

a)   all significant deficiencies in the design or operation of internal
     controls which could adversely affect the registrant's ability to record,
     process, summarize and report financial data and have identified for the
     registrant's auditors any material weaknesses in internal controls; and

b)   any fraud, whether or not material, that involves management or other
     employees who have a significant role in the registrant's internal
     controls, and

6.   The registrant's other certifying officer and I have indicated in this
     Amendment No. 1 to annual report whether there were significant changes in
     internal controls or in other factors that could significantly affect
     internal controls subsequent to the date of our most recent evaluation,
     including any corrective actions with regard to significant deficiencies
     and material weaknesses.

                                    /s/ Daniel M. Kuzmak
                                    --------------------
                                     Daniel M. Kuzmak
                                     Vice President, Finance and
                                     Chief Financial Officer
                                     April 1, 2003

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