EXHIBIT 10.1
                                  AMENDMENT TO

                       1995 EMPLOYEE STOCK PURCHASE PLAN

                                       OF

                               CYTYC CORPORATION.


  The 1995 Employee Stock Purchase Plan (the "Plan") is hereby amended by
deleting the second sentence of Article 4 thereof in its entirety and inserting
in lieu thereof the following:

  "The aggregate number of shares which may be issued pursuant to the Plan is
1,440,000, subject to adjustment as provided in Article 12."

Adopted by the Board of Directors on January 31, 2001.
Approved by the Stockholders on May 23, 2001.





                                      17


                               CYTYC CORPORATION

                       1995 EMPLOYEE STOCK PURCHASE PLAN


Article 1 - Purpose.
- -------------------

  This 1995 Employee Stock Purchase Plan (the "Plan") is intended to encourage
stock ownership by all eligible employees of Cytyc Corporation (the "Company"),
a Delaware corporation, and its participating subsidiaries (as defined in
Article 17) so that they may share in the growth of the Company by acquiring or
increasing their proprietary interest in the Company.  The Plan is designed to
encourage eligible employees to remain in the employ of the Company and its
participating subsidiaries.  The Plan is intended to constitute an "employee
stock purchase plan" within the meaning of Section 423(b) of the Internal
Revenue Code of 1986, as amended (the "Code").

Article 2 - Administration of the Plan.
- --------------------------------------

  The Plan may be administered by a committee appointed by the Board of
Directors of the Company (the "Committee").  The Committee shall consist of not
less than two members of the Company's Board of Directors.  The Board of
Directors may from time to time remove members from, or add members to, the
Committee.  Vacancies on the Committee, howsoever caused, shall be filled by the
Board of Directors.  The Committee may select one of its members as Chairman,
and shall hold meetings at such times and places as it may determine.  Acts by a
majority of the Committee, or acts reduced to or approved in writing by a
majority of the members of the Committee, shall be the valid acts of the
Committee.

  The interpretation and construction by the Committee of any provisions of the
Plan or of any option granted under it shall be final, unless otherwise
determined by the Board of Directors.  The Committee may from time to time adopt
such rules and regulations for carrying out the Plan as it may deem best,
provided that any such rules and regulations shall be applied on a uniform basis
to all employees under the Plan.  No member of the Board of Directors or the
Committee shall be liable for any action or determination made in good faith
with respect to the Plan or any option granted under it.

  In the event the Board of Directors fails to appoint or refrains from
appointing a Committee, the Board of Directors shall have all power and
authority to administer the Plan.  In such event, the word "Committee" wherever
used herein shall be deemed to mean the Board of Directors.

Article 3 - Eligible Employees.
- ------------------------------

  All employees of the Company or any of its participating subsidiaries whose
customary employment is more than 20 hours per week and (i) who are employed by
the Company as of December 13, 1995 or (ii) who have completed at least 90 days
of employment, shall be eligible to receive options under the Plan to purchase
common stock of the Company, and all eligible employees shall have the same
rights and privileges hereunder.  Persons who are eligible employees on the
first business day of any Payment Period (as defined in Article 5) shall receive
their options as of such day.  Persons who become eligible employees after any
date on which options are granted under the Plan shall be granted options on the
first day of the next succeeding Payment Period on which options are granted to
eligible employees under the Plan.  In no event, however, may an employee be
granted an option if such employee, immediately after the option was granted,
would be treated as owning stock possessing five percent or more of the total
combined voting power or value of all classes of stock of the Company or of any
parent corporation or subsidiary corporation, as the terms "parent corporation"
and "subsidiary corporation" are defined in Section 424(e) and (f) of the Code.
For purposes of determining stock ownership under this paragraph, the rules of
Section 424(d) of the Code shall apply, and stock which the employee may
purchase under outstanding options shall be treated as stock owned by the
employee.


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Article 4 - Stock Subject to the Plan.
- -------------------------------------

  The stock subject to the options under the Plan shall be shares of the
Company's authorized but unissued common stock, par value $.01 per share (the
"Common Stock"), or shares of Common Stock reacquired by the Company, including
shares purchased in the open market.  The aggregate number of shares which may
be issued pursuant to the Plan is 140,000, subject to adjustment as provided in
Article 12.  If any option granted under the Plan shall expire or terminate for
any reason without having been exercised in full or shall cease for any reason
to be exercisable in whole or in part, the unpurchased shares subject thereto
shall again be available under the Plan.

Article 5 - Payment Period and Stock Options.
- --------------------------------------------

  The first Payment Period during which payroll deductions will be accumulated
under the Plan shall commence on the date that the Common Stock of the Company
first begins trading in the public market, and shall end on December 31, 1996.
For the remainder of the duration of the Plan, Payment Periods shall consist of
the six-month periods commencing on December 1 and June 1 and ending on May 31
and November 30 of each twelve-month period, respectively.

  Twice each year, on the first business day of each Payment Period, the Company
will grant to each eligible employee who is then a participant in the Plan an
option to purchase on the last day of such Payment Period, at the Option Price
hereinafter provided for, a maximum of 300 shares, on condition that such
employee remains eligible to participate in the Plan throughout the remainder of
such Payment Period.  The participant shall be entitled to exercise the option
so granted only to the extent of the participant's accumulated payroll
deductions on the last day of such Payment Period.  If the participant's
accumulated payroll deductions on the last day of the Payment Period would
enable the participant to purchase more than 300 shares except for the 300-share
limitation, the excess of the amount of the accumulated payroll deductions over
the aggregate purchase price of the 300 shares shall be promptly refunded to the
participant by the Company, without interest.  The Option Price per share for
each Payment Period shall be the lesser of (i) 85% of the average market price
of the Common Stock on the first business day of the Payment Period and (ii) 85%
of the average market price of the Common Stock on the last business day of the
Payment Period, in either event rounded up to avoid fractions of a dollar other
than 1/4, 1/2 and 3/4.  The foregoing limitation on the number of shares subject
to option and the Option Price shall be subject to adjustment as provided in
Article 12.

  For purposes of the Plan, "average market price of the Common Stock" shall, on
the first business day of the first Payment Period, be the public offering price
on the effective date of the Company's initial public offering, and for any
other date shall be (i) the average (on that date) of the high and low prices of
the Common Stock on the principal national securities exchange on which the
Common Stock is traded, if the Common Stock is then traded on a national
securities exchange; or (ii) the last reported sale price (on that date) of the
Common Stock on the NASDAQ Stock Market, if the Common Stock is not then traded
on a national securities exchange; or (iii) the average of the closing bid and
asked prices last quoted (on that date) by an established quotation service for
over-the-counter securities, if the Common Stock is not reported on the NASDAQ
Stock Market; or (iv) if the Common Stock is not publicly traded, the fair
market value of the Common Stock as determined by the Committee after taking
into consideration all factors which it deems appropriate, including, without
limitation, recent sale and offer prices of the Common Stock in private
transactions negotiated at arm's length.

  For purposes of the Plan, the term "business day" means a day on which there
is trading on the NASDAQ National Market or the aforementioned national
securities exchange, whichever is applicable pursuant to the preceding
paragraph; and if neither is applicable, a day that is not a Saturday, Sunday or
legal holiday in the Commonwealth of Massachusetts.

  No employee shall be granted an option which permits the employee's right to
purchase stock under the Plan, and under all other Section 423(b) employee stock
purchase plans of the Company and any parent or subsidiary corporations, to
accrue at a rate which exceeds $25,000 of fair market value of such


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stock (determined on the date or dates that options on such stock were granted)
for each calendar year in which such option is outstanding at any time. The
purpose of the limitation in the preceding sentence is to comply with Section
423(b)(8) of the Code. If the participant's accumulated payroll deductions on
the last day of the Payment Period would otherwise enable the participant to
purchase Common Stock in excess of the Section 423(b)(8) limitation described in
this paragraph, the excess of the amount of the accumulated payroll deductions
over the aggregate purchase price of the shares actually purchased shall be
promptly refunded to the participant by the Company, without interest.

Article 6 - Exercise of Option.
- ------------------------------

  Each eligible employee who continues to be a participant in the Plan on the
last day of a Payment Period shall be deemed to have exercised his or her option
on such date and shall be deemed to have purchased from the Company such number
of full shares of Common Stock reserved for the purpose of the Plan as the
participant's accumulated payroll deductions on such date will pay for at the
Option Price, subject to the 300-share limit of the option and the Section
423(b)(8) limitation described in Article 5.  If the individual is not a
participant on the last day of a Payment Period, the he or she shall not be
entitled to exercise his or her option.  Only full shares of Common Stock may be
purchased under the Plan.  Unused payroll deductions remaining in a
participant's account at the end of a Payment Period by reason of the inability
to purchase a fractional share shall be carried forward to the next Payment
Period.

Article 7 - Authorization for Entering the Plan.
- -----------------------------------------------

  An employee may elect to enter the Plan by filling out, signing and delivering
to the Company an authorization:

  A. Stating the percentage to be deducted regularly from the employee's pay;

  B. Authorizing the purchase of stock for the employee in each Payment Period
   in accordance with the terms of the Plan; and

  C. Specifying the exact name or names in which stock purchased for the
   employee is to be issued as provided under Article 11 hereof.

Such authorization must be received by the Company at least ten business days
before the first day of the next succeeding Payment Period and shall take effect
only if the employee is an eligible employee on the first business day of such
Payment Period.

  Unless a participant files a new authorization or withdraws from the Plan, the
deductions and purchases under the authorization the participant has on file
under the Plan will continue from one Payment Period to succeeding Payment
Periods as long as the Plan remains in effect.

  The Company will accumulate and hold for each participant's account the
amounts deducted from his or her pay.  No interest will be paid on these
amounts.

Article 8 - Maximum Amount of Payroll Deductions.
- ------------------------------------------------

  An employee may authorize payroll deductions in an amount (expressed as a
whole percentage) not less than one percent (1%) but not more than ten percent
(10%) of the employee's total compensation, including base pay or salary and any
overtime, bonuses or commissions.

Article 9 - Change in Payroll Deductions.
- ----------------------------------------

  Deductions may not be increased or decreased during a Payment Period.
However, a participant may withdraw in full from the Plan.


                                      20


Article 10 - Withdrawal from the Plan.
- -------------------------------------

  A participant may withdraw from the Plan (in whole but not in part) at any
time prior to the last day of a Payment Period by delivering a withdrawal notice
to the Company.

  To re-enter the Plan, an employee who has previously withdrawn must file a new
authorization at least ten business days before the first day of the next
Payment Period in which he or she wishes to participate.  The employee's re-
entry into the Plan becomes effective at the beginning of such Payment Period,
provided that he or she is an eligible employee on the first business day of the
Payment Period.

Article 11 - Issuance of Stock.
- ------------------------------

  Certificates for stock issued to participants shall be delivered as soon as
practicable after each Payment Period by the Company's transfer agent.

  Stock purchased under the Plan shall be issued only in the name of the
participant, or if the participant's authorization so specifies, in the name of
the participant and another person of legal age as joint tenants with rights of
survivorship.

Article 12 - Adjustments.
- ------------------------

  Upon the happening of any of the following described events, a participant's
rights under options granted under the Plan shall be adjusted as hereinafter
provided:

  A. In the event that the shares of Common Stock shall be subdivided or
   combined into a greater or smaller number of shares or if, upon a
   reorganization, split-up, liquidation, recapitalization or the like of the
   Company, the shares of Common Stock shall be exchanged for other securities
   of the Company, each participant shall be entitled, subject to the conditions
   herein stated, to purchase such number of shares of Common Stock or amount of
   other securities of the Company as were exchangeable for the number of shares
   of Common Stock that such participant would have been entitled to purchase
   except for such action, and appropriate adjustments shall be made in the
   purchase price per share to reflect such subdivision, combination or
   exchange; and

  B. In the event the Company shall issue any of its shares as a stock dividend
   upon or with respect to the shares of stock of the class which shall at the
   time be subject to option hereunder, each participant upon exercising such an
   option shall be entitled to receive (for the purchase price paid upon such
   exercise) the shares as to which the participant is exercising his or her
   option and, in addition thereto (at no additional cost), such number of
   shares of the class or classes in which such stock dividend or dividends were
   declared or paid, and such amount of cash in lieu of fractional shares, as is
   equal to the number of shares thereof and the amount of cash in lieu of
   fractional shares, respectively, which the participant would have received if
   the participant had been the holder of the shares as to which the participant
   is exercising his or her option at all times between the date of the granting
   of such option and the date of its exercise.

  Upon the happening of any of the foregoing events, the class and aggregate
number of shares set forth in Article 4 hereof which are subject to options
which have been or may be granted under the Plan and the limitations set forth
in the second paragraph of Article 5 shall also be appropriately adjusted to
reflect the events specified in paragraphs A and B above.  Notwithstanding the
foregoing, any adjustments made pursuant to paragraphs A or B shall be made only
after the Committee, based on advice of counsel for the Company, determines
whether such adjustments would constitute a "modification" (as that term is
defined in Section 424 of the Code).  If the Committee determines that such
adjustments would constitute a modification, it may refrain from making such
adjustments.

  If the Company is to be consolidated with or acquired by another entity in a
merger, a sale of all or substantially all of the Company's assets or otherwise
(an "Acquisition"), the Committee or the board of directors of any entity
assuming the obligations of the Company hereunder (the "Successor Board") shall,
with respect to options then outstanding under the Plan, either (i) make
appropriate provision for the


                                      21


continuation of such options by arranging for the substitution on an equitable
basis for the shares then subject to such options either (a) the consideration
payable with respect to the outstanding shares of the Common Stock in connection
with the Acquisition, (b) shares of stock of the successor corporation, or a
parent or subsidiary of such corporation, or (c) such other securities as the
Successor Board deems appropriate, the fair market value of which shall not
materially exceed the fair market value of the shares of Common Stock subject to
such options immediately preceding the Acquisition; or (ii) terminate each
participant's options in exchange for a cash payment equal to the excess of (a)
the fair market value on the date of the Acquisition, of the number of shares of
Common Stock that the participant's accumulated payroll deductions as of the
date of the Acquisition could purchase, at an option price determined with
reference only to the first business day of the applicable Payment Period and
subject to the 300-share, Code Section 423(b)(8) and fractional-share
limitations on the amount of stock a participant would be entitled to purchase,
over (b) the result of multiplying such number of shares by such option price.

  The Committee or Successor Board shall determine the adjustments to be made
under this Article 12, and its determination shall be conclusive.

Article 13 - No Transfer or Assignment of Employee's Rights.
- -----------------------------------------------------------

  An option granted under the Plan may not be transferred or assigned and may be
exercised only by the participant.

Article 14 - Termination of Employee's Rights.
- ---------------------------------------------

  Whenever a participant ceases to be an eligible employee because of
retirement, voluntary or involuntary termination, resignation, layoff,
discharge, death or for any other reason, his or her rights under the Plan shall
immediately terminate, and the Company shall promptly refund, without interest,
the entire balance of his or her payroll deduction account under the Plan.
Notwithstanding the foregoing, eligible employment shall be treated as
continuing intact while a participant is on military leave, sick leave or other
bona fide leave of absence, for up to 90 days, or for so long as the
participant's right to re-employment is guaranteed either by statute or by
contract, if longer than 90 days.

  If a participant's payroll deductions are interrupted by any legal process, a
withdrawal notice will be considered as having been received from the
participant on the day the interruption occurs.

Article 15 - Termination and Amendments to Plan.
- -----------------------------------------------

  Unless terminated sooner as provided below, the Plan shall terminate on
December 12, 2005.  The Plan may be terminated at any time by the Company's
Board of Directors but such termination shall not affect options then
outstanding under the Plan.  It will terminate in any case when all or
substantially all of the unissued shares of stock reserved for the purposes of
the Plan have been purchased.  If at any time shares of stock reserved for the
purpose of the Plan remain available for purchase but not in sufficient number
to satisfy all then unfilled purchase requirements, the available shares shall
be apportioned among participants in proportion to the amount of payroll
deductions accumulated on behalf of each participant that would otherwise be
used to purchase stock, and the Plan shall terminate.  Upon such termination or
any other termination of the Plan, all payroll deductions not used to purchase
stock will be refunded, without interest.

  The Committee or the Board of Directors may from time to time adopt amendments
to the Plan provided that, without the approval of the stockholders of the
Company, no amendment may (i) increase the number of shares that may be issued
under the Plan; (ii) change the class of employees eligible to receive options
under the Plan, if such action would be treated as the adoption of a new plan
for purposes of Section 423(b) of the Code; or (iii) cause Rule 16b-3 under the
Securities Exchange Act of 1934 to become inapplicable to the Plan.


                                      22


Article 16 - Limits on Sale of Stock Purchased under the Plan.
- -------------------------------------------------------------

  The Plan is intended to provide shares of Common Stock for investment and not
for resale.  The Company does not, however, intend to restrict or influence any
employee in the conduct of his or her own affairs.  An employee may, therefore,
sell stock purchased under the Plan at any time the employee chooses, subject to
compliance with any applicable federal or state securities laws, subject to any
applicable policies of the Company governing sale by employees of shares of
Common Stock, and subject to any restrictions imposed under Article 21 to ensure
that tax withholding obligations are satisfied.  THE EMPLOYEE ASSUMES THE RISK
OF ANY MARKET FLUCTUATIONS IN THE PRICE OF THE STOCK.

Article 17 - Participating Subsidiaries.
- ---------------------------------------

  The term "participating subsidiary" shall mean any present or future
subsidiary of the Company, as that term is defined in Section 424(f) of the
Code, which is designated from time to time by the Board of Directors to
participate in the Plan.  The Board of Directors shall have the power to make
such designation before or after the Plan is approved by the stockholders.

Article 18 - Optionees Not Stockholders.
- ---------------------------------------

  Neither the granting of an option to an employee nor the deductions from his
or her pay shall constitute such employee a stockholder of the shares covered by
an option until such shares have been actually purchased by the employee.

Article 19 - Application of Funds.
- ---------------------------------

  The proceeds received by the Company from the sale of Common Stock pursuant to
options granted under the Plan will be used for general corporate purposes.

Article 20 - Notice to Company of Disqualifying Disposition.
- -----------------------------------------------------------

  By electing to participate in the Plan, each participant agrees to notify the
Company in writing immediately after the participant transfers Common Stock
acquired under the Plan, if such transfer occurs within two years after the
first business day of the Payment Period in which such Common Stock was
acquired.  Each participant further agrees to provide any information about such
a transfer as may be requested by the Company or any subsidiary corporation in
order to assist it in complying with the tax laws.  Such dispositions generally
are treated as "disqualifying dispositions" under Sections 421 and 424 of the
Code, which have certain tax consequences to participants and to the Company and
its participating subsidiaries.

Article 21 - Withholding of Additional Income Taxes.
- ---------------------------------------------------

  By electing to participate in the Plan, each participant acknowledges that the
Company and its participating subsidiaries are required to withhold taxes with
respect to the amounts deducted from the participant's compensation and
accumulated for the benefit of the participant under the Plan, and each
participant agrees that the Company and its participating subsidiaries may
deduct additional amounts from the participant's compensation, when amounts are
added to the participant's account, used to purchase Common Stock or refunded,
in order to satisfy such withholding obligations.  Each participant further
acknowledges that when Common Stock is purchased under the Plan the Company and
its participating subsidiaries may be required to withhold taxes with respect to
all or a portion of the difference between the fair market value of the Common
Stock purchased and its purchase price, and each participant agrees that such
taxes may be withheld from compensation otherwise payable to such participant.
It is intended that tax withholding will be accomplished in such a manner that
the full amount of payroll deductions elected by the participant under Article 7
will be used to purchase Common Stock.  However, if amounts sufficient to
satisfy applicable tax withholding obligations have not been withheld from
compensation otherwise payable to any participant, then, notwithstanding any
other provision of the Plan, the Company may withhold such taxes from the
participant's accumulated payroll deductions and apply the net amount to the
purchase of Common Stock, unless the participant pays to the Company, prior to
the exercise date, an


                                      23


amount sufficient to satisfy such withholding obligations. Each participant
further acknowledges that the Company and its participating subsidiaries may be
required to withhold taxes in connection with the disposition of stock acquired
under the Plan and agrees that the Company or any participating subsidiary may
take whatever action it considers appropriate to satisfy such withholding
requirements, including deducting from compensation otherwise payable to such
participant an amount sufficient to satisfy such withholding requirements or
conditioning any disposition of Common Stock by the participant upon the payment
to the Company or such subsidiary of an amount sufficient to satisfy such
withholding requirements.

Article 22 - Governmental Regulations.
- -------------------------------------

  The Company's obligation to sell and deliver shares of Common Stock under the
Plan is subject to the approval of any governmental authority required in
connection with the authorization, issuance or sale of such shares.

  Government regulations may impose reporting or other obligations on the
Company with respect to the Plan.  For example, the Company may be required to
identify shares of Common Stock issued under the Plan on its stock ownership
records and send tax information statements to employees and former employees
who transfer title to such shares.

Article 23 - Governing Law.
- --------------------------

  The validity and construction of the Plan shall be governed by the laws of the
State of Delaware, without giving effect to the principles of conflicts of law
thereof.

Article 24 - Approval of Board of Directors and Stockholders of the Company.
- ---------------------------------------------------------------------------

  The Plan was adopted by the Board of Directors on December 13, 1995 and was
approved by the stockholders of the Company on December 13, 1995; and the Plan
was amended on July 10, 1998 by action of the Compensation Committee of the
Board of Directors.


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