IONICS, INCORPORATED
__________________________________________________________________________
                              211,583 Shares
                               Common Stock
__________________________________________________________________________

    This Prospectus relates to the offer and sale of up to an aggregate of
211,583 shares of Common Stock, $1.00 par value per share (the "Shares"), of
Ionics, Incorporated ("Ionics" or the "Company"), by five Company
shareholders (the "Selling Shareholders").  The Selling Shareholders may
sell the Shares at market prices prevailing at the time of the sale or at
prices otherwise negotiated, or may transfer a portion of the Shares by way
of gift.  See "PLAN OF DISTRIBUTION."  The Selling Shareholders and certain
persons who purchase shares from them, including broker-dealers acting as
principals who may resell the Shares, may be deemed "underwriters," as that
term is defined in the Securities Act of 1933, as amended (the "Securities
Act").  See "PLAN OF DISTRIBUTION" and "SELLING SHAREHOLDERS."

    None of the proceeds from the resale of the Shares will be received by
the Company.  The Company is responsible for the expenses incurred in
connection with the registration of the Shares.  The Selling Shareholders
will pay or assume brokerage commissions or other similar charges incurred
in the sale of the Shares.  The Company has agreed to indemnify the Selling
Shareholders against certain liabilities, including liabilities under the
Securities Act.

    The Company's Common Stock is traded on the New York Stock Exchange
under the symbol "ION."  The last reported sale price for the Common Stock
on Ocober 2, 1996 was $46.75, as reported by the New York Stock Exchange.


    THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY
THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY
STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY
OF THIS PROSPECTUS.  ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

    No person has been authorized to give any information or to make any
representation other than those contained in this Prospectus in
connection with the offering made hereby, and if given or made, such
information or representation must not be relied upon as having been
authorized by the Company.  Neither the delivery of this Prospectus nor
any sale made hereunder shall, under any circumstances, create any
implication that information herein is correct as of any time subsequent
to the date hereof.

               The date of this Prospectus is October 3, 1996.




                           AVAILABLE INFORMATION

    The Company is subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith files reports, proxy statements and other information
with the Securities and Exchange Commission (the "Commission").  Such
reports, proxy statements and other information are available for inspection
and copying at the public reference facilities maintained by the Commission
at 450 5th Street, N.W., Washington, D.C. 20549, and at the following
regional offices of the Commission:  75 Park Place, 14th Floor, New York,
New York 10007 and 219 South Dearborn Street, Room 1204, Chicago, Illinois
60604.  Copies of such material can also be obtained from the Public
Reference Section of the Commission at 450 5th Street, N.W., Washington,
D.C. 20549 at prescribed rates.  The Common Stock of the Company is listed
for trading on the New York Stock Exchange and such material may also be
inspected and copied at the New York Stock Exchange, 20 Broad Street, New
York, New York.

    The Company has filed with the Commission a Registration Statement on
Form S-3 (including all amendments thereto, the "Registration Statement")
under the Securities Act, with respect to the Shares offered hereby.  This
Prospectus does not contain all information set forth in the Registration
Statement, certain parts of which are omitted in accordance with the rules
and regulations of the Commission.  For further information regarding the
Company and the Shares offered hereby, reference is hereby made to the
Registration Statement and to the exhibits and schedules filed therewith.
Statements contained in this Prospectus regarding the contents of any
agreement or other document filed as an exhibit to the Registration
Statement are not necessarily complete, and in each instance reference is
made to the copy of such agreement filed as an exhibit to the Registration
Statement, each such statement being qualified in all respects by such
reference.  The Registration Statement, including the exhibits and schedules
thereto, may be inspected at the public reference facilities maintained by
the Commission at 450 5th Street, N.W., Room 1024, Washington, D.C. 20549
and copies of all or any part thereof may be obtained from such office upon
payment of the prescribed fees.

                   INFORMATION INCORPORATED BY REFERENCE

    The following documents filed by the Company with the Commission
pursuant to the Exchange Act are incorporated in this Prospectus by
reference as of their respective dates (File No. 1-7211):

    1. The Company's Annual Report on Form 10-K for the fiscal year ended
       December 31, 1995;

    2. Quarterly Reports on Form 10-Q for the fiscal quarters ended March
       31, 1996 and June 30, 1996;

    3. The section entitled "Description of Securities to be Registered"
       contained in the Company's Registration Statement on Form 8-A filed
       with the Commission on September 27, 1990.

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    All documents subsequently filed by the Company pursuant to Section
13(a), 13(c), 14 or 15(d) of the Exchange Act, prior to the termination of
the offering made hereby, shall be deemed to be incorporated by reference
in this Prospectus from the date of filing of such documents.  Any
statement contained in a document incorporated or deemed to be incorporated
by reference herein shall be deemed to be modified or superseded for
purposes of this Prospectus to the extent that a statement contained herein
or in any other subsequently filed document which is also deemed to be
incorporated by reference herein modifies or supersedes such statement.
Any such statement so modified or superseded shall not be deemed, except as
so modified or superseded, to constitute a part of this Prospectus.

    The Company will provide without charge to each person to whom a
Prospectus is delivered, on the written or oral request of such person, a
copy of any or all of the documents described above (other than exhibits to
such documents).  Requests for such copies should be directed to Stephen
Korn, Clerk, Ionics, Incorporated, 65 Grove Street, Watertown,
Massachusetts  02172 (telephone: 617-926-2500).

                                THE COMPANY

    Ionics is a separations technology company involved worldwide in the
manufacture and sale of membranes and related equipment for the
purification, concentration, treatment and analysis of water and
wastewater, in the supply of purified water, food and chemical products,
and in the sale of bottled water and home water purifiers.  The Company's
business activities are divided into three segments:  membranes and related
equipment; water, food and chemical supply; and consumer products.

    Ionics was incorporated in Massachusetts in 1948.  The Company's
principal executive offices are located at 65 Grove Street, Watertown,
Massachusetts  02172 and its telephone number is (617) 926-2500.

                              USE OF PROCEEDS

    The Company will not receive any of the proceeds from the sale of the
Shares by the Selling Shareholders.















                                    -3-





                           SELLING SHAREHOLDERS

    The following table sets forth certain information regarding beneficial
ownership of the Shares as of September 15, 1996 and the number of Shares
which may be offered for the account of the Selling Shareholders from time
to time:


                             Shares       Shares To   Shares          Percent
                            Beneficially  be Sold   Beneficially      of Class
                            Owned Prior   in the    Owned After        After
Selling Shareholder       to the Offering Offering  the Offering(1)  Offering(1)
                                                         
Michael Doolan                 4,703          800       3,903             *
Brigstock House
Hall Hill
Brigstock, Northamptonshire
England NN143EZ

Peter W. Duddleston           13,324       10,000       3,324             *
1587 Oak Avenue
Arden Hills, MN  55112

Randy R. Willardsen           39,973       35,000       4,973             *
9730 Wellington Lane
Woodbury, MN  55125

William L. Putnam            331,567      165,783     165,784             1.1%
 and Carol B. Putnam(2)
5562 Azure Way
Long Beach, CA  90803


                         
(1) Assumes all Shares offered are sold.

(2) Includes shares of Common Stock held by certain trusts established
    primarily for the benefit of Mr. and Mrs. Putnam and their family.  Mr.
    and Mrs. Putnam are co-trustees of such trusts.

*   Less than 1%.


    Messrs. Doolan, Duddleston and Willardsen are former shareholders of
Separation Technology, Inc., a Minnesota corporation which was acquired by
the Company on July 25, 1996.  Mr. Willardsen currently serves as
President, and Mr. Duddleston as Vice President, of such subsidiary.  The
Selling Shareholders acquired their Shares from the Company in non-public
offerings pursuant to the provisions of Section 4(2) under Regulation D
under the Securities Act.


                                    -4-




                           PLAN OF DISTRIBUTION

    The Shares offered hereby may be sold from time to time by the Selling
Shareholders acting as principals for their own account.  The Company is
responsible for all expenses incurred in connection with the registration
of the Shares.  The Selling Shareholders will pay brokerage commissions or
other charges and expenses incurred in the sale of the Shares.  The Company
has agreed to indemnify the Selling Shareholders against certain
liabilities, including liabilities under the Securities Act.

    The distribution of the Shares by the Selling Shareholders is not
currently subject to any underwriting agreement.  The Shares covered by
this Prospectus may be sold by the Selling Shareholders or by pledgees,
donees, transferees or other successors in interest from time to time, and
the Company believes that it is the intention of the Selling Shareholders
to complete such sales within ninety (90) days of the date of this
Prospectus.  Such sales may be made at fixed prices that may be changed, at
market prices prevailing at the time of sale, at prices related to such
prevailing market prices, or at negotiated prices.  Such sales may be
effected in the over-the-counter market, on the New York Stock Exchange or
on any other exchange on which the Shares may then be listed.  The Shares
may be sold by one or more of the following:  (a) one or more block trades
in which a broker or dealer so engaged will attempt to sell all or a
portion of the Shares held by the Selling Shareholders as agent but may
position and resell a portion of the block as principal to facilitate the
transaction; (b) purchases by a broker or dealer as principal and resale by
such broker or dealer for its account pursuant to this Prospectus; and (c)
ordinary brokerage transactions and transactions in which the broker
solicits purchasers.  The Selling Shareholders will effect such
transactions by selling Shares through broker-dealers, and such broker-
dealers will receive compensation in negotiated amounts in the form of
discounts, concessions, commissions or fees which will be paid by the
Selling Shareholders.  Such brokers or dealers and the Selling Shareholders
may be deemed to be "underwriters" within the meaning of the Securities
Act, in connection with such sales, and any commissions received by such
broker-dealers may be deemed to be underwriting compensation.  One or more
Selling Shareholders may also transfer some of their Shares by way of gift
pursuant to this Prospectus.

    The Company will provide a copy of this Prospectus to the New York
Stock Exchange pursuant to Rule 153 under the Securities Act.

    State Street Bank & Trust Company, c/o Boston Equiserve, 150 Royall
Street, Canton, Massachusetts 02021, is the transfer agent for the
Company's Common Stock.








                                    -5-






                               LEGAL MATTERS

    Certain legal matters with respect to the issuance of the Shares are
being passed upon for the Company by Stephen Korn, Vice President and
General Counsel of the Company.  Mr. Korn beneficially owns 43,317 shares
of Common Stock, which number includes 41,800 shares subject to options, as
to which Mr. Korn has the right to acquire beneficial ownership, and 294
shares (as of June 30, 1996) in the Company's Section 401(k) Plan for the
account of Mr. Korn.

                                  EXPERTS

    The consolidated financial statements and schedule of Ionics,
Incorporated and Subsidiaries as of December 31, 1995 and 1994, and for
each of the three years in the period ended December 31, 1995, incorporated
by reference in this Prospectus have been so incorporated herein in
reliance on the reports of Coopers & Lybrand L.L.P., independent
accountants, given on the authority of that firm as experts in accounting
and auditing.
































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No dealer, salesperson or any other
person has been authorized to give any
information or to make any representations
not contained in this Prospectus and, if
given or made, such information or 
representations must not be relied upon
as having been authorized by the Company.
This Prospectus does not constitute an                211,583 Shares
offer to sell, or a solicitation of an 
offer to sell, any securities other than 
the registered securities to which it               IONICS, INCORPORATED
relates, or an offer to or solicitation
of any person in any jurisdiction where 
such an offer or solicitation would be 
unlawful.  Neither the delivery of this                Common Stock
Prospectus nor any sale made hereunder
shall, under any circumstances, create
an implication that the information 
contained herein is correct as of any
time subsequent to the date hereof.

_______________________________________
                                                    _____________________
      TABLE OF CONTENTS
                             Page                        PROSPECTUS
                                                    _____________________
Available Information......... 2
Information Incorporated by
 Reference.................... 2
The Company................... 3
Use of Proceeds............... 3
Selling Shareholders.......... 4
Plan of Distribution.......... 5
Legal Matters................. 6
Experts....................... 6                       October 3, 1996

                                                                         














                                    -7-