<PAGE>
                                                                 Exhibit 10.35

                                  June 1, 1999


CONFIDENTIAL
------------

Brian J. Smith
271 Corona Avenue
Pelham, New York  10803

Dear Brian:

     This letter agreement (this "Agreement") formalizes the agreement that we
have reached regarding your voluntary resignation from all positions you hold
(whether as an officer or employee) with Boron, LePore & Associates, Inc. (the
"Company") as of October 31, 1999 (the "Resignation Date").  The purpose of this
Agreement is to establish an amicable arrangement for ending your employment
relationship.  For purposes of this Agreement, all references to the "Company"
shall include Boron, LePore & Associates, Inc., a Delaware corporation, and any
of its subsidiaries.  Reference is made to the Employment Agreement between you
and the Company dated March 1, 1999 (the "Employment Agreement"). Capitalized
terms used herein and not defined shall have the meaning set forth in the
Employment Agreement.  Except as set forth herein, this Agreement supersedes the
Employment Agreement and the Employment Agreement is of no further force or
effect.

     In exchange for the promises of you and the Company set forth below, you
and the Company agree as follows:

A.   TERMINATION OF EMPLOYMENT.  As of June 1, 1999 you hereby resign as
Corporate Executive Vice President of Boron, LePore & Associates, Inc. and from
any other officer positions currently held by you with Boron, LePore &
Associates, Inc. or any of its subsidiaries.  You shall remain employed by the
Company as a Special Assistant for Mergers and Acquisitions from June 1, 1999
until the Resignation Date, at which date you agree to voluntary resign and
terminate your employment from all positions and service relationships you hold
with the Company.  Said resignations are hereby accepted by the Company.
Notwithstanding any termination of your employment by the Company prior to
October 31, 1999, in the event of any such termination you shall continue to be
entitled to receive all of the

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 2


benefits provided under this Agreement as if you had remained employed by the
Company through October 31, 1999.

B.   SEVERANCE; COMPENSATION.  The Company shall continue to make payments in
the amount of your Base Salary from the period June 1, 1999 to May 31, 2000
(with such amounts through the Resignation Date constituting compensation as an
employee and the amounts thereafter through May 31, 2000 representing
severance).  You shall also receive $112,500, the full amount of your target
bonus set for 1999, when such bonus would otherwise be paid. In consideration of
these payments, you are hereby delivering to the Company in paragraph I hereto a
release of claims, and you agree, as a condition to the Company's obligation to
pay you any amounts which are due you on or after the Resignation Date pursuant
to this Agreement, to deliver another release in the same form on the
Resignation Date.  The foregoing payments shall be payable in accordance with
the Company's payroll practices for its executive officers, in all cases subject
to withholding under applicable law; provided, however, that the Company in its
sole discretion may elect to pay at any time any remaining amounts due to you
hereunder in a lump sum; and provided further, that in the event of a Change of
Control of the Company (as such term is defined in your current Employment
Agreement), all remaining amounts payable to you hereunder shall be paid in full
in a lump sum immediately upon the occurrence of such Change of Control.  The
Company agrees to pay you at your Base Salary rate for any unused vacation time
you have accrued through June 1, 1999, based on Company policy related to such
vacation time, which shall be paid promptly upon termination of your employment
relationship with the Company.  Other than the payments described in this
Agreement, you shall not be entitled to any additional payments from the Company
relating to your employment with the Company or the termination thereof,
including, without limitation, any amounts specified in the Employment
Agreement.

C.   STOCK OPTIONS.  Notwithstanding any provision to the contrary contained in
the stock option agreements between you and the Company or the governing stock
option plan (collectively, the "Option Agreements"),  all stock options to
purchase shares of Common Stock held by you which are unvested as of June 1,
1999 shall terminate as of June 1, 1999, and you will have the period of time
following the Resignation Date (or such earlier date on which your service
relationship with the Company terminates due to your voluntary resignation,
death or disability) specified in the Option Agreements and the governing stock
option plan  to exercise such stock options which have vested as of June 1,
1999.

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 3


D.   BENEFITS. You and your beneficiaries shall be entitled to continue to
receive, at the Company's expense, the medical, dental, life and disability
insurance benefits as are currently provided to you (or comparable coverage
pursuant to COBRA) until the earlier of (a) the date on which you secure
permanent employment and become eligible for participation in such employer's
insurance programs or (b) June 1, 2000, at which time all such benefits shall
terminate, except as otherwise provided by law.  Until the termination of your
employment with the Company, you shall be entitled to continue to participate as
an employee in any existing 401(k) plan of the Company, and after the
termination of your employment with the Company, your rights with regard to any
such 401(k) plan shall be as provided by law and as may be provided in any such
plan with regard to former employees of the Company.  Your eligibility to
participate in the Company's other employee benefit plans and programs will
cease on June 1, 1999, except as otherwise required by law.

E.   NON-COMPETITION; CONFIDENTIALITY.  You hereby acknowledge that until
October 31, 1999, you are still subject to the terms and covenants contained in
Article 8 of the Employment Agreement by and between you and the Company, at
which time such terms shall be of no further force or effect.  You hereby
reaffirm and readopt all of the terms and covenants of Sections 7 and 9 of the
Employment Agreement as if they were completely restated herein. Except as set
forth in this paragraph E, the Employment Agreement is hereby terminated and of
no further force and effect.

F.   RETURN OF PROPERTY.  You hereby acknowledge that all documents, records,
materials, software, equipment, credit cards, information and other physical or
intellectual property that have come into your possession or been produced or
created by you in connection with your employment with or for the Company
("Property") have been and remain the sole property of the Company.  You hereby
acknowledge that you have returned to the Company all such Property or will have
returned all such Property on or prior to October 31, 1999 except that any
Company-paid credit cards will be returned on or prior to June 1, 1999.

G.   LITIGATION COOPERATION.  You agree to reasonably cooperate with the Company
in (i) the defense, prosecution or investigation of any claims or actions which
already have been brought or threatened, or which may be brought or threatened
in the future against or on behalf of the Company and its affiliates and (ii)
responding to, cooperating with, or contesting any governmental audit,
inspection, inquiry or investigation, in either case that relate to events or
occurrences that transpired during your employment or association with the
Company;

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 4


provided, however, that such cooperation shall not materially and adversely
affect you or expose you to an increased probability of civil or criminal
litigation. Your full cooperation in connection with such claims or actions
shall include, without implication of limitation: being available to meet with
counsel to prepare for discovery or trial; to testify truthfully as a witness
when reasonably requested and at reasonable times designated by the Company; and
to meet with counsel or other designated representative of the Company to
prepare responses to and to cooperate with the Company's processing of
governmental audits, inspections, inquiries or investigations. You agree that
you will maintain the confidences and privileges of the Company. You will be
reimbursed by the Company only for any reasonable out-of-pocket expenses that
you reasonably incur in connection with such cooperation, including but not
limited to reasonable attorneys' fees and expenses, subject to reasonable and
satisfactory documentation. The Company will not exercise their rights under
this paragraph so as to interfere with your ability to engage in gainful
employment and shall endeavor to schedule your responsibilities hereunder so as
not to interfere with your schedule so long as you promptly provide timely
alternative dates on which you can fulfill your obligations hereunder.

H.   NON-DISPARAGEMENT AND COOPERATION DURING TRANSITION.  Each of us agrees not
to make or cause to be made, directly or indirectly, any statement to any person
criticizing or disparaging the other or any of the Company's stockholders,
directors, officers or employees or commenting unfavorably or falsely on the
character, business judgment, business practices or business reputation of the
other or any of the Company's stockholders, directors, officers or employees.
You agree that from the date of your receipt of this Agreement, you will
cooperate fully with the Company in arranging for an orderly and professional
transition of your responsibilities.  Each of us further agrees that he or it
will present the circumstances of your departure in a light that will not
reflect unfavorably on you or the Company.

I.   RELEASE.  You hereby irrevocably and unconditionally release, acquit, and
forever discharge the Company and its affiliates, securityholders, subsidiaries,
affiliates and related entities and their respective current and former
partners, members, officers, directors, agents, and employees, from any and all
claims, demands, or causes of action based upon any past action, omission, or
event, whether known or unknown, and whether or not in litigation which you may
have had from the beginning of time or which could be asserted by another on
your behalf, based on any action, omission, or event through the date hereof
relating to your employment at the Company and/or your status as a stockholder
and/or optionholder of the Company.  This release includes actions claiming
violation of Title VII of the Civil Rights Act

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 5


of 1964, as amended, 42 U.S.C. 2000e et seq., the Age Discrimination in
Employment Act, the Americans with Disabilities Act, all other labor laws of
New Jersey, and any other federal, state, or local law, order or regulation.
This release also includes any claims for wrongful discharge or that the Company
has dealt with you unfairly or in bad faith, and actions raising tortious
claims, actions raising any claim of express or implied contract of employment,
or any other cause of action or claims of violation of common law. This release
is for any and all relief, without regard to its form or characterization.
Included in this release are any and all claims for attorneys' fees and for
future damages allegedly arising from the alleged continuation of the effects of
any past action, omission or event. Notwithstanding anything in this release to
the contrary, this release shall not be construed to limit your right to enforce
this Agreement, or any Stock Option Agreements to which you are a party relating
to stock options remaining outstanding in accordance with the terms hereof.

J.   INDEMNIFICATION AND INSURANCE.  From and after the date of this Agreement,
the Company agrees that it will indemnify you and hold you harmless against any
losses, claims, damages, liabilities, costs and expenses, including without
limitation attorneys' fees and expenses, relating to or arising out of your
employment in any capacity with the Company to the same extent and upon the same
terms, conditions and limitations as indemnification shall be provided to other
executive officers of the Company who are not directors and shall provide, at
the Company's expense, Directors' and Officers' insurance coverage to the same
extent and upon the same terms and conditions as such insurance may be provided
to other executive officers of the Company from time to time.  Consistent with
the foregoing, the Company shall have the right to assume the defense of any
proceeding to which you are a party or otherwise subject with counsel of its
choice (with representation by your own counsel following any such assumption to
be at your expense except in cases of conflict of interest under applicable
standards of professional conduct, in which case the Company shall be
responsible for such expense), and advancement of expenses shall be made upon
determination by the Board of Directors to advance such expenses and receipt of
an undertaking by you to repay such expenses if it shall be determined that you
are not entitled to indemnification under applicable law.  Without limitation of
the foregoing, you shall be entitled to indemnification in accordance with the
terms of Article V of the Company's By-laws as currently in effect as a former
officer of the Company, notwithstanding any future Changes of Control or
amendment thereof, the terms and conditions of which are incorporated by
reference herein to govern the provision of indemnification to you by the
Company.

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 6


K.   MISCELLANEOUS.

     You are advised to consult with an attorney before signing this Agreement.

     By signing this Agreement, you acknowledge that you are doing so
voluntarily and only after consultation with your personal attorney.  You also
acknowledge that you are not relying on any representations by the undersigned
or any other representative of the Company concerning the meaning of any aspect
of this Agreement other than as set forth in this Agreement.

     You acknowledge that you have been given the opportunity, if you so
desired, to consider this Agreement for seven (7) days before executing it.
If not signed by you and returned to Mr. Patrick G. LePore, Chief Executive
Officer, Boron, LePore & Associates, Inc., 17-17 Route 208 North, Fair Lawn,
New Jersey 07410, so that he receives it by close of business on the eighth
(8th) day after your receipt of the Agreement, this Agreement will not be valid.
In addition, if you breach any of the conditions of the Agreement within the
seven (7) day period, the offer of this Agreement will be withdrawn and your
execution of the Agreement will not be valid. In the event that you execute and
return this Agreement within seven (7) days or less of the date of its delivery
to you, you acknowledge that such decision was entirely voluntary and that you
had the opportunity to consider this letter agreement for the entire seven (7)
day period. The Company acknowledges that for a period of seven (7) days from
the date on which you execute this Agreement, you shall retain the right to
revoke this Agreement by written notice delivered to Mr. LePore at the address
indicated above, and that this Agreement shall not become effective or
enforceable until the expiration of such revocation period.

     In the event of any dispute, this Agreement will be construed as a whole,
will be interpreted in accordance with its fair meaning, and will not be
construed strictly for or against either you or the Company.  The laws of
Delaware will govern any dispute about this Agreement, including any
interpretation or enforcement of this Agreement.  In the event that any
provision or portion of a provision of this Agreement shall be determined to be
unenforceable, the remainder of this Agreement shall be enforced to the fullest
extent possible as if such provision or portion of a provision were not
included.  This Agreement may be modified only by a written agreement signed by
you and an authorized representative of the Company.

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 7


     In the event of a dispute between the parties concerning their respective
rights and obligations under this Agreement or under any stock option agreement
to which you and the Company are party, that the parties are unable to resolve
amicably between themselves within sixty (60) days of proper notice from one
party to another, such dispute shall be settled by arbitration in the State of
New Jersey in an expedited manner in accordance with the Commercial Rules of the
American Arbitration Association by a duly registered arbitrator to be selected
jointly by the parties.  The decision of the arbitrator shall be final and
binding upon the parties.  Notwithstanding anything to the contrary herein, the
provisions of this paragraph shall not apply to any equitable remedies to which
any party may be entitled.

     Notwithstanding the foregoing, it is specifically understood and agreed
that any breach of the provisions of Sections E, F and H hereof is likely to
result in irreparable injury to the nonbreaching party and/or its affiliates,
that the remedy at law alone will be an inadequate remedy for such breach and
that, in addition to any other remedy it may have, the nonbreaching party shall
be entitled to enforce the specific performance of Sections E, F and H of this
Agreement and to seek both temporary and permanent injunctive relief (to the
extent permitted by law).

     All notices, requests, demands and other communications hereunder shall be
in writing and shall be deemed to have been duly given if mailed by overnight
mail (with receipt acknowledgment received), delivered personally or mailed by
certified or registered mail (return receipt requested) as follows:

     To the Company:     Boron, LePore & Associates, Inc.
                         17-17 Route 208 North
                         Fair Lawn, New Jersey  07410
                         Attention:  Patrick G. LePore, President and CEO

     To the Employee:    Brian Smith
                         271 Corona Avenue
                         Pelham, New York 10803


or to such other address of which any party may notify the other parties as
provided above. Notices shall be effective as of the date of delivery.

                                                              PGL ____  BJS ____
<PAGE>

Brian J. Smith
June 1, 1999
Page 8


     The Company is executing this Agreement with you on behalf of itself and
each of its subsidiaries and hereby represents to you that the execution and
delivery of this Agreement by the Company and the performance of the Company's
obligations hereunder have been duly authorized by all necessary action on the
part of the Company.

     If you agree to these terms, please sign and date below and return this
Agreement to the undersigned within the time limitation set forth above.

                                 Sincerely,

                                 BORON, LEPORE & ASSOCIATES, INC.


                                 By: /s/ Patrick G. LePore
                                     -----------------------------
                                 Name:  Patrick G. LePore
                                 Title: Chief Executive Officer


ACCEPTED AND AGREED TO:



/s/ Brian J. Smith
-----------------------------
Brian J. Smith

Dated:
      -----------------------


                                                            PGL _____ BJS _____
<PAGE>


Brian J. Smith
June 1, 1999
Page 9


SPOUSAL CONSENT: I ACKNOWLEDGE THAT I HAVE READ THE FOREGOING AGREEMENT AND THAT
I UNDERSTAND THE CONTENTS THEREOF AND HEREBY ACCEPT AND AGREE TO THE FOREGOING
TERMS.



-----------------------------
Name:

Dated:
      -----------------------

                                                            PGL _____ BJS _____