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                                                                    EXHIBIT 10.1

March 3, 2000

Mr. Robert L. Kamba
/Address redacted/

Dear Robert:

This letter confirms our offer to you of employment by PSINet Inc. (the
"Company"), and sets forth the terms and conditions which shall govern such
employment as outlined below. This offer is subject to satisfactory completion
of reference checks and ratification by the Company's Board of Directors, but
otherwise shall remain open until COB on Friday, March 10, 2000.

1.       EMPLOYMENT:

a) The Company agrees to employ you as Senior Vice President and President,
Global Hosting Operations, reporting to the President and Chief Operating
Officer (COO) of the Company or his designee. This is a corporate officer
position and as an officer of the Company you must stand for election by the
Board of Directors each year. You accept the employment and agree to begin work
on or before Monday, March 20, 2000, and remain in the employ of the Company,
and, except during vacation periods and sickness, to provide during standard
business hours a minimum of forty (40) hours per week of management services to
the Company, as determined by and under the direction of the COO.

b) During your employment you will, except during vacations, periods of illness,
and other absences beyond your reasonable control, devote your best efforts,
skill and attention to the performance of your duties on behalf of the Company.

2.       COMPENSATION:

a) BASE SALARY. The Company shall pay you a base salary at the rate of $225,000
per annum. Your base salary shall be subject to additional increases at the
discretion of the Company's Board of Directors. Your base salary shall be
payable in such installments as the Company regularly pays its other salaried
employees, subject to such deductions and withholdings as may be required by law
or by further agreement with you.

b) BONUS COMPENSATION. The Company will pay you a bonus upon the successful
completion of the objectives established for your performance. The performance
criteria will be issued separately by the President and COO, and may be changed,
with mutual fairness, from time to time as situations develop. The target bonus
for the period ending December 31, 2000 (start date through December 31, 2000)
will be a total of up to $112,500. Separate criteria will be established for
your entitlement for the year starting January 1, 2001.

c) INCENTIVE STOCK OPTIONS. Effective upon your start date, PSINet Inc. shall
grant you options, subject to Board approval, to purchase 125,000 shares of
PSINet Inc.'s common stock (the "Options") pursuant to its Executive Stock
Incentive Plan (the "Plan"). Such Options shall be evidenced by an option
agreement in such form as required by the Plan. Among other terms and provisions
prescribed by the Plan, the option agreement shall provide that (a) the exercise
price of the Options shall be the price per share of the Company's common stock
as reported by the NASDAQ Stock Market at the close of business on your start
date, (b) the Options shall not be exercisable after the expiration of ten (10)
years from the date such Options are granted, and (c) the stock shall vest
ratably, monthly, over forty-eight (48) months, provided that for each

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month's vesting purposes you continue to be employed full time by the Company or
one of its subsidiaries during such month, and provided that the Company's Board
of Directors ratifies, no less often than annually, that you have met the
performance standards and criteria set for you for the preceding period.

3.       EMPLOYEE BENEFITS:

a) You shall be provided employee benefits, including (without limitation)
401(k), four (4) weeks' paid vacation, and life, health, accident and disability
insurance under the Company's plans, policies and programs available to
employees in accordance with the provisions of such plans, policies, and
programs.

b) You shall be reimbursed for automobile expenses to a maximum of $800 per the
Company's Car Allowance Policy.

c) You shall be eligible to receive financial planning and tax assistance from
PriceWaterhouseCoopers and the Mason Companies up to a value of $8,000.

4.       TERMINATION:

a) Your employment with the Company may be terminated by the Company at any time
for "Cause" as defined in Section 4(c) hereof. Upon such termination, the
Company will provide written notice whether it has elected to use the
non-competition restrictions set forth in Section 5(a) hereof. Your employment
may also be terminated by the Company at any time without Cause provided the
Company shall have given you one hundred eighty (180) days' prior written notice
of such termination. That written notice must state whether the Company has
elected to use the non-Competition restriction (which decision may not be
rescinded). In addition, your employment may be terminated by you at any time
for any reason, provided you shall have given the Company at least thirty (30)
days' prior written notice of such termination. By the 30th day the Company must
notify you in writing whether it has elected to use the non-Competition
restriction. Such decision may not be rescinded. Failure of the Company to so
notify you shall result in the non-Competition restriction not being in place.

b) Subject to your compliance with your obligations under Section 5 hereof, in
the event that your employment terminates or is terminated by you or the Company
for any reason other than for Cause, and the Company has elected to use the
non-Competition restriction, you shall be entitled, for a period of twelve (12)
months after termination of employment, to the following (collectively, the
"Termination Payments"): (i) your then current rate of base salary as provided
in Section 2; (ii) all life insurance and health benefits, disability insurance
and benefits and reimbursement theretofore being provided to you; and (iii)
Company contributions, to the extent permitted by applicable law, to a SEP-IRA,
Keogh or other retirement mechanism selected by you sufficient to provide the
same level of retirement benefits you would have received if you had remained
employed by the Company during such 12-month period. The Company shall make up
the difference in cash payments directly to you to the extent that applicable
law would not permit it to make such contributions.

c) The Company shall have "Cause" for your termination of your employment by
reason of any breach of your agreement not to compete pursuant to Section 5
hereof, your committing an act materially adversely affecting the Company which
constitutes wanton or willful misconduct, your conviction of a felony, or any
material breach by you of this Agreement.

5.       AGREEMENT NOT TO COMPETE.

a) In consideration of your employment pursuant to this Agreement and for other
good and valuable consideration, the receipt and adequacy of which is hereby
acknowledged, you covenant to and agree with the Company that, so long as you
are employed by the Company under this Agreement and for a period of twelve (12)
months following the termination of such employment (but only if the Company has
elected to enforce the

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restriction), you shall not, without the prior written consent of the Company,
either for yourself or for any other person, firm or corporation, manage,
operate, control, participate in the management, operation or control of or be
employed by any other person or entity which is engaged in providing
Internet-related network or communications services competitive with the
Internet-related network or communication services offered to customers by the
Company as of the date of termination or within six (6) months thereafter. The
foregoing shall in no event restrict you from: (i) writing or teaching, whether
on behalf of for-profit, or not-for-profit institution(s); (ii) investing
(without participating in management or operation) in the securities of any
private or publicly traded corporation or entity; or (iii) after termination of
employment, becoming employed by a hardware, software or other vendor to the
Company, provided that such vendor does not offer network or communication
services that are competitive with the Internet-related network or
communications services offered by the Company as of the date of termination of
employment or within six (6) months thereafter.

b) You may request permission from the Company's Board of Director's to engage
in activities which would otherwise be prohibited by Section 5(a). The Company
shall respond to such request within thirty (30) days after receipt. The Company
will notify you in writing if it becomes aware of any breach or threatened
breach of any of the provisions in Section 6(a), and you shall have thirty (30)
days after receipt of such notice in which to cure or prevent the breach, to the
extent that you are able to do so. You and the Company acknowledge that any
breach or threatened breach by you of any of the provisions in Section 5(a)
above cannot be remedied by the recovery of damages, and agree that in the event
of any such breach or threatened breach which is not cured with such 30-day
period, the Company may pursue injunctive relief for any such breach or
threatened breach. If a court of competent jurisdiction determines that you
breached any of such provisions, you shall not be entitled to any Termination
Payments from and after date of the breach. In such event, you shall promptly
repay any Termination Payments previously made plus interest thereon from the
date of such payment(s) at 12% per annum. If, however, the Company has suspended
making such Termination Payments and a court of competent jurisdiction finally
determines that you did not breach such provision or determines such provision
to be unenforceable as applied to your conduct, you shall be entitled to receive
any suspended Termination Payment, plus interest thereon from the date when due
at 12% per annum. The Company may elect (once) to continue paying the
Termination Payments before a final decision has been made by the court.

6. INTELLECTUAL PROPERTY. Ownership of Work Product. All copyrights, patents,
trade secrets, or other intellectual property rights associated with any ideas,
concepts, techniques, inventions, processes, or works of authorship developed or
created by you during the course of performing the Company's work (collectively
the "Work Product") shall belong exclusively to the Company and shall, to the
extent possible, be considered a work made for hire for the Company within the
meaning of Title 17 of the United States Code. You automatically assign, and
shall assign at the time of creation of the Work Product, without any
requirement of further consideration, any right, title, or interest you may have
in such Work Product, including any copyrights or other intellectual property
rights pertaining thereto. Upon request of the Company, you shall take such
further actions, including execution and delivery of instruments of conveyance,
as may be appropriate to give full and proper effect to such assignment.

7.       TRANSFERABILITY.

a) As used in this Agreement, the term "Company" shall include any successor to
all or part of the business or assets of the Company who shall assume and agree
to perform this Agreement.

This Agreement shall inure to the benefit of and be enforceable by you and your
personal or legal representatives, executors, administrators, heirs,
distributees, devisees and legatees.

b) Except as provided under paragraph (a) of this Section 7, neither this
Agreement nor any of the rights or obligations hereunder shall be assigned or
delegated by any party hereto without the prior written consent of the other
party.

8.       SEVERABILITY. The invalidity or unenforceability of any particular
provision of this Agreement shall not affect the other provisions hereof, and
this Agreement shall be construed in all respects as

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if such invalid or unenforceable provision were omitted. If a court of competent
jurisdiction determines that any particular provision of this Agreement is
invalid or unenforceable, the court shall restrict the provision so as to be
enforceable. However, if the provisions of Section 5 shall be restricted, a
proportional reduction shall be made in the payments under Section 4.

9.       ENTIRE AGREEMENT; WAIVERS. This letter Agreement contains the entire
agreement of the parties concerning the subject matter hereof and supersedes
and cancels all prior agreements, negotiations, correspondence, undertakings
and communications of the parties, oral or written. No waiver or modification
of any provision of this Agreement shall be effective unless in writing and
signed by both parties.

10.      NOTICES. Any notices, requests, instruction or other document to be
given hereunder shall be in writing and shall be sent certified mail, return
receipt requested, addressed to the party intended to be notified at the
address of such party as set for at the head of this agreement or such other
address as such party may designate in writing to the other.

11.      GOVERNING LAW. THIS LETTER AGREEMENT SHALL BE SUBJECT TO, GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT
REFERENCE TO ITS PRINCIPLES OF CONFLICTS OF LAW.

12.      COUNTERPARTS. This letter Agreement may be executed in one or more
counterparts, each of which shall be deemed an original and all of which
shall be one and the same instrument.

Please confirm your agreement with the foregoing by signing and returning one
copy of this letter Agreement to the undersigned, whereupon this letter
agreement shall become a binding agreement between you and the Company.

Sincerely,

PSINet Inc.



By:      /s/Harold S. Wills
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         HAROLD S. WILLS
         PRESIDENT AND CHIEF OPERATING OFFICER





Accepted and Agreed to as of March 3, 2000:



By:      /s/Robert L. Kamba



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