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                                                                    EXHIBIT 4.01

                            MERRIMAC INDUSTRIES, INC.
                            2001 STOCK PURCHASE PLAN

         1. Purpose. The purpose of this 2001 Stock Purchase Plan ("Plan") is to
provide an opportunity for employees of Merrimac Industries, Inc. (the
"Company") and of its present and future Subsidiaries to purchase shares of
Common Stock of the Company and thereby to have an additional incentive to
contribute to the prosperity of the Company. It is the intention of the Company
that the Plan qualify as an "employee stock purchase plan" within the meaning of
Section 423 of the Code. The provisions of the Plan shall be construed so as to
extend and limit participation in a manner consistent with that section of the
Code.

         2. Definitions. The following words have the following meanings unless
a different meaning is plainly required by the context.

                  (a) "Agreement" means the Option Offer and Stock Purchase
Agreement setting forth the terms and conditions pursuant to which shares of
Common Stock may be purchased by an Employee under the Plan.

                  (b) "Board" means the Board of Directors of the Company.

                  (c) "Code" means the Internal Revenue Code of 1986, as
amended.

                  (d) "Committee" means the Stock Purchase Plan Committee
appointed under Section 4 to administer the Plan.

                  (e) "Common Stock" means the common stock, par value $0.01, of
the Company.

                  (f) "Compensation" means regular fixed basic compensation in
effect for an Employee on the date of the Agreement, and, at the discretion of
the Committee, such discretion to be exercised uniformly with respect to all
Employees, any bonus or overtime pay, but in all cases excluding any
contribution to an employee benefit plan or other similar payment or
contribution.

                  (g) "Employee" means any employee, including any officer, who
has been in the service of the Company or of any Subsidiary which has been
designated by the Company as a Subsidiary eligible to participate in the Plan
for at least one consecutive year immediately prior to the date on which he
enters into an Agreement with the Company hereunder, other than any employee
working in a country whose laws make participation in the Plan impractical
and/or illegal.

                  (h) "Fair Market Value" means, with respect to a share of the
Common Stock on any date, (i) the closing sale price of the Common Stock on the
American Stock Exchange on such date or (ii) if there is no sale of the Common
Stock on such Exchange on such date, the
average of the bid and asked prices on such Exchange at the close of the market
on such business day.

                  (i) "Interest" means interest at the rate of 5% a year.

                  (j) "Purchase Date" means the last day of a period of 27
months beginning with the date of the offer of an Agreement hereunder.

                  (k) "Subsidiary" means any corporation in which the Company
owns directly or indirectly a majority of the issued and outstanding shares of
stock.

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         3. Stock.

                  (a) The total number of shares of Common Stock which may be
sold under the Plan shall not exceed 250,000 shares except to the extent of
adjustments authorized by Section 6(a)(x). These shares may consist in whole or
in part of unissued shares or treasury shares.

                  (b) If an Agreement entered into under the Plan shall expire
or terminate for any reason, any unpurchased shares subject thereto shall
(unless the Plan shall have been terminated) again be available for the purposes
of the Plan.

         4. Administration. The Board shall appoint a Stock Purchase Plan
Committee consisting of at least two members of the Board who shall serve at the
pleasure of the Board. The Committee shall administer the Plan and shall, when
and as authorized by the Board from time to time, offer to enter into an
Agreement under the Plan with each Employee who elects to participate in the
Plan and shall have the sole authority to interpret the Plan and any Agreement.
All decisions made by the Committee shall be final.

         5. Number of Shares Which an Employee May Purchase. An Employee may
elect to purchase pursuant to the terms of an Agreement entered into hereunder
that number of shares of Common Stock having a Fair Market Value equal to such
percentage of his Compensation as such Employee elects, up to 10% of his
Compensation, but not more than that proportion of the total number of shares
being offered as of the date of such Agreement equal to his Compensation divided
by the aggregate Compensation of all Employees who elect to participate as of
the date of such Agreements. Any fractional shares resulting from these
calculations shall be eliminated. Such Employee may elect to purchase fewer than
the total number of shares which he is entitled to elect under the preceding
sentence. Notwithstanding the foregoing, no Agreement may be entered into
hereunder between the Company and any Employee:

                  (a) if such Employee (or any other person whose stock
ownership shall be attributed to such Employee pursuant to Section 424(d) of the
Code), immediately after execution of the Agreement, owns stock (including that
which he may purchase under the Agreement and any other stock which the Employee
may purchase under outstanding options and other Agreements) possessing 5% or
more of the total combined voting power or value of all classes of stock of the
Company or of any of its Subsidiaries; or

                  (b) if such Agreement permits such Employee's rights to
purchase stock under all employee stock purchase plans (within the meaning of
Section 423 of the Code) of the Company
and its Subsidiaries to accrue at a rate which exceeds a Fair Market Value of
$25,000 (determined at the time of offer of such Agreement or the granting of
such option agreement, as the case may be) for any one calendar year.

         6. Terms and Conditions of Agreements.

                  (a) Agreements shall be in such form as the Committee shall
from time to time approve and shall comply with the following terms and
conditions:

                           (i) The purchase price per share shall not be less
         than the lesser of (A) 85% of the Fair Market Value of a share of
         Common Stock on the date designated by the Committee as the date that
         offers to enter into Agreements are made or (B) 85% of the Fair Market
         Value on the date such option is exercised.

                           (ii) The Employee in his Agreement shall direct the
         Company or the Subsidiary, as the case may be, to withhold from his
         Compensation, throughout the duration of the Agreement, amounts
         sufficient to accumulate over the term of the Agreement the aggregate
         purchase price of the shares which are covered by the Agreement.

                           (iii) The stated term of each Agreement shall be
         27 months.

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                           (iv) The Agreement shall not be assignable or
         transferable except by will or by the laws of descent and distribution.
         During the lifetime of an Employee who is a party to such an Agreement
         the shares which are covered thereby may be purchased only by him.

                           (v) Subject to earlier purchase pursuant to Section
         6(a)(vii) or (viii), each Agreement shall provide that the Employee on
         the Purchase Date shall purchase all of the shares covered thereby
         unless he shall have, in the manner provided for in the Agreement,
         notified the Company on or before the Purchase Date, that he does not
         desire to purchase any of such shares or that he desires to purchase
         fewer than all of such shares. Each Agreement shall also provide that
         on the Purchase Date the funds then on deposit for the Employee's
         account shall be applied to the purchase price of such shares, and that
         the excess, if any, over the purchase price of purchased shares shall
         forthwith be paid to the Employee.

                           (vi) Each Agreement shall provide that the Employee
         who has entered into it may at any time on or before the Purchase Date
         terminate the Agreement in its entirety by delivering written notice to
         the Company. Upon such termination all funds held for the Employee's
         account, plus Interest shall be paid promptly to the Employee within 30
         business days.

                           (vii) Each Agreement shall provide that, after it has
         been in effect for at least 90 days and subject to Section 9, the
         Employee, from time to time (but no more than twice) prior to the
         Purchase Date, on written notice received by the Company at least five
         business days prior to the end of any calendar month, may elect to
         purchase on the last day of such month or of any subsequent month
         (unless the Purchase Date shall first occur) all or fewer than all of
         the shares covered by the Agreement.

                           (viii) If the employment by the Company and/or its
         Subsidiaries of an Employee who has entered into an Agreement hereunder
         shall terminate, the Agreement shall terminate immediately and within
         30 business days of such termination the Employee shall be paid all
         funds held for the Employee's account, plus Interest; provided,
         however, that if any termination of employment is due to either normal,
         early or disability retirement under the Company's qualified plans, the
         Employee shall have the right within 30 days thereafter (or on or
         before the Purchase Date if it occurs before the expiration of such
         period) to elect to purchase all or fewer than all of the shares
         covered by the Agreement; and further provided, that if the Employee
         shall die while in the employ of the Company or a Subsidiary during the
         term of the Agreement, his estate, personal representative, or
         beneficiary shall have the right, at any time within 12 months of his
         death (or on or before the Purchase Date if it occurs before the
         expiration of such period), to elect to purchase all or fewer than all
         of the shares covered by the deceased employee's Agreement.

                           (ix) Each Agreement shall provide that the purchase
         price shall be payable in United States dollars upon any purchase of
         shares thereunder by transfers, to the extent required to cover the
         purchase price, of amounts held for the Employee's account,
         supplemented, if necessary, by payments from the Employee in the form
         of cash, certified check, bank draft or money order payable to the
         order of the Company.

                           (x) If there shall be any increase or decrease in the
         number of issued shares of the Common Stock resulting from a
         subdivision or a consolidation or reclassification of shares, or the
         payment of a stock dividend, appropriate adjustments shall be made by
         the Board in the aggregate number of shares subject to the Plan, the
         formula determining the number of shares with respect to which
         Agreements may be entered into with any particular Employee and the
         number of shares and price per share subject to outstanding Agreements,
         provided, however, that any fractional shares resulting from any such
         adjustment shall be eliminated.

                           (xi) If the Company shall be the surviving or
         resulting corporation in any merger or consolidation, any Agreement
         entered into under the Plan shall apply to the shares to which a holder
         of the number of shares of Common Stock covered by the Agreement would
         have been entitled.

                  (b) Agreements under the Plan may contain such other
provisions as the Committee may deem appropriate, provided such other provisions
do not violate any applicable statute or regulation, apply uniformly to all
Employees and are not inconsistent with the terms of the Plan.


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         7. Rights as a Stockholder. An Employee who is a party to an Agreement
entered into hereunder shall have no rights as a stockholder with respect to
shares covered by such Agreement until the date of the issuance of the shares to
him. No adjustment will be made for dividends or other rights for which the
record date is prior to the date of such issuance.

         8. Employee Representations. If, at the time of any purchase under an
Agreement under the Plan, in the opinion of counsel for the Company, it is
necessary or desirable, in order to comply with any applicable law or regulation
relating to the sale of securities, that the Employee shall agree that he will
purchase the shares that are subject to the Agreement for investment and not
with any present intention to resell the same, the employee will, upon the
request of the Company, execute and deliver to the Company an agreement to such
effect.
         9. Effective Date of Plan. The Plan became effective on April 20, 2001,
subject to approval within 12 months of adoption by the holders of a majority of
the shares of the Common Stock present in person or by proxy at any special or
annual meeting of the stockholders. Agreements may be entered into following
such date, provided that they shall expressly provide that no shares may be
issued thereunder unless and until the Plan shall have been approved by
stockholders.
         10. Term of Plan. No offer to enter into an Agreement shall be made
pursuant to the Plan after April 19, 2011. The Board may terminate the Plan at
any time, provided, however, that any such termination shall not affect any
Agreement then outstanding under the Plan.

         11. Amendment of Plan. The Board may amend the Plan at any time, and
from time to time, provided, however, that, without the further approval of the
holders of a majority of the shares of the Common Stock present in person or by
proxy at any special or annual meeting of the stockholders, the Board may not
(a) increase (other than by adjustments provided in Section 6(a)(x)) the maximum
number of shares which may be covered by all Agreements entered into under the
Plan (either in the aggregate or with respect to any individual) or (b) change
the persons or category of persons eligible to participate in the Plan.



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