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Exhibit 10.44

Employment and Transition Agreement

        This Employment and Transition Agreement (the "Agreement") is entered
into this 30th day of June 2003 between Lawrence B. Evans ("Evans") and Aspen
Technology, Inc., a Delaware corporation (the "Company").

Recitation

        Evans was the founder of the Company, served as its Chairman and Chief
Executive Officer for 21 years after its founding in 1981, and built the Company
from a start-up with eight founding employees to a public company with more than
1,800 employees. Evans has an international reputation in the field of process
modeling, simulation, and optimization. The Company considers it desirable to
retain the services of Evans for a transition period, to continue his active
involvement with the Company, and to benefit from his reputation in the field.

Agreements

        Evans and the Company agree as follows:

        1.    Term of Full-Time Employment.    Evans will continue to serve as a
full-time employee of the Company through June 30, 2004 ("Full-Time Term").
During the Full-Time Term Evans will receive a base salary of $325,000 per year,
plus all the employee benefits provided to other executive management employees,
excluding participation in the Company's bonus program except as provided in
paragraph 4(f) below. In addition, Evans will participate in the Company's stock
option program to the extent that grants of stock options are appropriate to his
role as Chairman and a Director of the Company.

        2.    Activities During Full-Time Term.    During the Full-Time Term,
Evans will perform the following activities.

a.Service as Chairman.    Subject to the approval of the Company's Board of
Directors, it is expected that Evans will continue to serve as Chairman of the
Company. Evans will not be eligible for additional cash compensation in
consideration for this service, but will be eligible for director stock options,
as approved by the Compensation Committee. These director stock options shall,
to the extent possible under applicable law, be eligible for ISO treatment and
shall be in the same amount and under the same terms as provided for
non-employee directors, notwithstanding the fact that Evans is an employee.
Without limiting the foregoing, as soon as is practicable after execution of
this Agreement, Evans will receive a grant of 24,000 stock options, 6,000 of
which shall be immediately vested, and the remaining 18,000 of which shall vest
at the rate of 2,000 per calendar quarter beginning with the calendar quarter
ending September 30, 2003. The strike price for these 24,000 options shall be
the closing price of the stock on the date immediately preceding the date on
which the option is granted. Thereafter, Evans shall receive director stock
options annually in an amount that shall not be less than the amount awarded to
any other director.

b.Company Activities.    Evans will perform such activities as are mutually
agreed between him and the CEO. It is expected that these activities will
include: (1) supporting the Company's Customer Relationship Management Program
initiative, (2) supporting specific customer sales pursuits, and
(3) representing the Company at major technology and marketing events.

c.Non-Company Activities.    Evans may devote up to one-half of his time to
non-Company activities, provided that such activities are appropriate in view of
his responsibilities to the Company and do not conflict with the interests of
the Company.

        3.    Part-Time Employment.    At the end of the Full-Time Term, Evans
will become a part-time employee for a period of four years through June 30,
2008 (the "Part-Time Term"). During the

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Part-Time Term, Evans will receive a base salary of $162,500 per year plus all
the employee benefits provided to other executive management employees,
excluding participation in the Company's bonus program (except as provided in
paragraph 4(f) below), and he will participate in the Company's stock option
program only to the extent that grants of stock options are appropriate to his
role as Chairman and a Director of the Company. During the Part-Time Term, Evans
will make himself available to provide services to the Company for up to 30 days
per year at the direction of the Company's CEO. Additional services may be
obtained at the rate of $5,000 per day upon the mutual agreement of the Company
and Evans. The Company will reimburse Evans for all expenses reasonably incurred
by him in performing services for the Company during the Part-Time Term. Evans
and his family shall be entitled to continue to participate in the Company's
group health insurance plans during both the Full-Time Term and the Part-Time
Term, and Evans' entitlement to continuation health care coverage under COBRA
shall commence at the end of the Part-Time Term.

        4.    Miscellaneous Support.    During both the Full-Time Term and the
Part-Time Term:

a.Office and Professional.    The Company will provide Evans an office in the
Company facilities with secretarial support, a laptop or equivalent computer and
network access, and the Company will reimburse Evans for reasonable travel
expenses to participate in external professional activities, such as meetings of
the NAE, AIChE and other professional organizations and service on university
advisory committees. Reimbursement for travel expenses for external professional
activities will not exceed $20,000 in any one year without prior approval from
the Company's CEO.

b.Stock Options.    Evans will be eligible to participate in any option exchange
program offered by the Company to the executive management team who report to
the Company's CEO. Evans will be an employee and, therefore, his options will
continue to vest and be valid according to their terms.

c.Adjustment for Inflation.    All of the dollar amounts mentioned in the
Agreement will be adjusted on an annual basis, as of each January 1, to account
for inflation. The adjustment will be made on the basis of the consumer price
index for Boston, Massachusetts. There will be no decrease in the dollar amounts
in the case of disinflation.

d.Attorney's Fees.    The Company will reimburse Evans for reasonable attorney's
fees and expenses incurred in connection with the negotiation of this Agreement.

e.Death or Disability.    Should Evans become unable to provide services under
this Agreement due to disability during either the Full-Time Term or the
Part-Time Term, the Company will place Evans on disability leave of absence for
the remainder of the Full-Time and Part-Time Terms (or for such portion of such
Terms as Evans remains disabled) and during such leave shall continue to pay the
amounts due under this Agreement to Evans. Disability shall be determined by a
physician reasonably satisfactory to both Evans and the Company. In the event
that Evans dies during either the Full-Time Term or the Part-Time Term, the
Company shall continue to pay the amounts due under this Agreement to Evans'
estate and all of Evans' unvested stock options shall immediately become vested.

f.Eligibility for Bonuses.    Notwithstanding any provision of this Agreement to
the contrary, during the Full-Time Term and the Part-Time Term, Evans shall be
eligible to receive bonuses under the Company's bonus plan on the basis as
bonuses are awarded to other executive management employees of the Company, but
only to the extent necessary to reimburse Evans for amounts that have been
deducted from his salary since April 16, 2002, under the Company's Salary
Deduction Program.

        5.    Termination of Change of Control Agreement.    The Change in
Control Agreement dated August 12, 1997 between the Company and Evans is
terminated by mutual consent and is no longer in effect.

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        6.    Public Announcement.    The Company agrees to review with Evans
any proposed announcements, internal company-wide communications or other public
disclosures related to his employment status with the Company prior to their
release. No such communications will be released without Evans's prior approval,
which will not be unreasonably withheld. Evans agrees that he and his agents
will not otherwise publicize or disclose, directly or indirectly, the existence
of this Agreement, the terms thereof, or the circumstances giving rise to the
Agreement, to anyone other than Evans's attorney, accountant, financial advisor
and members of his immediate family or as required by law.

        7.    Release by Evans.    In consideration of the agreements by the
Company set forth in this Agreement, Evans, on behalf of himself, his heirs,
successors, current and former agents, representatives, attorneys, assigns,
executors, beneficiaries, and administrators, hereby releases and forever
discharges the Company and each and all of its officers, directors,
shareholders, employees, representatives and agents from any and all charges,
complaints, claims, liabilities, obligations, promises, Agreements,
controversies, damages, actions, causes of action, suits, rights, demands,
costs, losses, debts and expenses (including attorneys' fees) related in any way
to Evans's employment with or separation from the Company, as well as all claims
under Title VII of the Civil Rights Act of 1964, the Americans with Disabilities
Act, the Age Discrimination in Employment Act, the Older Worker Benefit
Protection Act, the Employee Retirement Income Security Act of 1974, the
National Labor Relations Act, the Family and Medical Leave Act, any other
federal, state or local anti-discrimination laws, and any other contractual or
tort claims relating to Evans's employment or separation from employment with
the Company; provided, however, that nothing in this Release shall prevent Evans
from seeking to enforce his rights under this Agreement.

        In exchange for the agreements by Evans set forth in this Agreement, the
Company and all of its respective present and former directors, officers,
employees, agents, successors, assigns and affiliates, hereby releases and
forever discharges Evans, from any and all suits, claims, demands, debts, sums
of money, damages, interest, attorneys' fees, expenses, actions, causes of
action, judgments, accounts, promises, contracts, agreements, and any and all
claims of law or in equity, whether now known or unknown, which they now have or
ever have had against him, including, but not limited to claims under any
federal state or local statute, regulation, ordinance or common law, related to
or arising out of Evans' employment with the Company; provided, however, that
nothing in this Release shall prevent the Company from seeking to enforce its
rights under this Agreement.

        8.    Procedures.    By signing this Agreement, Evans acknowledges and
agrees that:

a.he has been afforded a reasonable and sufficient period of time for
deliberation thereon and for negotiation of the terms thereof;

b.he has carefully read and understands the terms of this Agreement;

c.he has signed this Agreement freely and voluntarily and without duress or
coercion and with full knowledge of its significance and consequences and of the
rights relinquished, surrendered, released and discharged hereunder;

d.the only consideration for signing this Agreement are the terms stated herein
and no other promise, Agreement or representation of any kind has been made to
him by any person or entity whatsoever to cause him to sign this Agreement;

e.that the Company did offer him a minimum period of at least twenty-one
(21) days after his receipt of this Agreement to review it; and

f.that the Company advised him that he had the opportunity to consult an
attorney before signing this Agreement.

This Agreement may be revoked, in writing sent to the CEO of the Company by
Evans at any time during the period of seven (7) calendar days following the
date of execution by Evans. If such seven (7) day revocation period expires
without Evans exercising his revocation right, then the obligations of this
Agreement will then become fully effective as more fully set forth herein.

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        9.    Integration; Severability; Binding on Successors.    This
Agreement constitutes an integrated Agreement, containing the entire
understanding of the parties with respect to the matters addressed herein and,
except as set forth in this Agreement, no representations, warranties or
promises have been made or relied on by the parties. This Agreement shall
prevail over any prior communications between the parties or their
representations relative to matters addressed herein. Notwithstanding the
foregoing, if any court of competent jurisdiction should determine that any part
of this Agreement is unenforceable, the part of the Agreement so determined
shall be considered severed from the rest of this Agreement, and the rest of
this Agreement shall remain in full force and effect. This Agreement shall be
binding upon the Company, its successors and assigns.

        10.    Applicable Law; Arbitration.    This Agreement shall be
interpreted, enforced and governed under the laws of the Commonwealth of
Massachusetts. Any disputes arising under this Agreement shall be submitted to
binding arbitration by the American Arbitration Association ("AAA"). The
arbitration shall be conducted in Boston, Massachusetts, before a single
arbitrator, and the arbitrator shall be selected and the arbitration conducted
pursuant to the AAA's rules governing commercial arbitration.

 
 
/s/  LAWRENCE B. EVANS       

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Lawrence B. Evans
 
 
Aspen Technology, Inc.
 
 
By:
 
/s/  ILLEGIBLE      

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Title:
 
/s/  ILLEGIBLE      

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Exhibit 10.44

Employment and Transition Agreement