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                                                                EXHIBIT 10.05(a)
                                                                ----------------

                         REGISTRATION RIGHTS AGREEMENT

           This Registration Rights Agreement (the "Agreement"), dated as of
September 11, 1996, by and between Occupational Health + Rehabilitation Inc, a
Delaware corporation (the "Company"), and Argosy Health, L.P., a Pennsylvania
limited partnership (the "Holder").

           WHEREAS, the Company and the Holder are entering into this Agreement
to provide for the registration of certain shares of the Company's common stock
which the Holder is acquiring pursuant to an Asset Purchase Agreement (the
"Purchase Agreement") dated September 11, 1996;

           NOW, THEREFORE, in consideration of the terms and conditions as set
forth herein, the Company covenants and agrees with the Holder as follows:

           1.   Certain Definitions. As used in this Agreement, the following
                -------------------
terms shall have the following respective meanings:

                "Commission" shall mean the Securities and Exchange Commission,
                ------------
or any other federal agency at the time administering the Securities Act.

                "Common Stock" shall mean the Common Stock, $.001 par value, of
                --------------
the Company, as constituted as of the date of this Agreement.

                "Exchange Act" shall mean the Securities Exchange Act of 1934,
                --------------
as amended, or any similar federal statute, and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

                "Holder" shall mean the person who is the then record owner of
                --------
Restricted Stock.

                "Registration Expenses" shall mean the expenses so described in
                -----------------------
Section 6.

                "Restricted Stock" shall mean the Shares, excluding shares which
                ------------------
have been (a) registered under the Securities Act pursuant to an effective
registration statement filed thereunder and disposed of in accordance with the
registration statement covering them or (b) publicly sold pursuant to Rule 144
under the Securities Act.

                "Securities Act" shall mean the Securities Act of 1933, as
                ----------------
amended, or any similar federal statute, and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.
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                "Shares" shall mean the shares of Common Stock issued pursuant
                --------
to the Purchase Agreement.

           2.   Restrictive Legend. Each certificate representing the Restricted
                ------------------
Stock shall bear a legend stating in substance:

           THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
           SECURITIES ACT OF 1933 AS AMENDED OR ANY STATE SECURITIES LAWS AND
           MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR
           HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER SAID ACT AND SUCH LAWS
           OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO
           THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE
           OR HYPOTHECATION DOES NOT VIOLATE THE PROVISIONS THEREOF OR UNLESS
           SOLD PURSUANT TO RULE 144 PROMULGATED UNDER SAID ACT.

           A certificate shall not be required to bear such legend if in the
opinion of counsel satisfactory to the Company, the securities represented
thereby may be publicly sold without registration under the Securities Act.

           3. Notice of Proposed Transfer. Prior to any proposed transfer of any
              ---------------------------
Restricted Stock (other than under the circumstances described in Section 4),
the Holder thereof shall give written notice to the Company of its intention to
effect such transfer. Each such notice shall describe the manner of the proposed
transfer and, if requested by the Company, shall be accompanied by an opinion of
counsel satisfactory to the Company to the effect that the proposed transfer may
be effected without registration under the Securities Act, whereupon the Holder
of such stock shall be entitled to transfer such stock in accordance with the
terms of its notice; provided, however, that no such opinion of counsel shall be
required for a distribution by a partnership to its partners of such stock in
respect of such interest. Each certificate for shares of Restricted Stock
transferred as above provided shall bear the legend set forth in Section 2,
except that such certificate shall not bear such legend if (i) such transfer is
in accordance with the provisions of Rule 144 (or any other rule permitting
public sale without registration under the Securities Act) or (ii) the opinion
of counsel referred to above is to the further effect that the transferee and
any subsequent transferee (other than an affiliate of the Company) would be
entitled to transfer such securities in a public sale without registration under
the Securities Act. The restrictions provided for in this Section 3 shall not
apply to securities which are not required to bear the legend prescribed by
Section 2 in accordance with the provisions of that Section.

           4.  Incidental Registration. If the Company at any time proposes to
               -----------------------
register any of its securities under the Securities Act for sale to the public,
whether for its own account or for the account of other securityholders or both
(except with respect to registration statements on Forms S-4, S-8 or another
form not available for registering the Restricted Stock for sale to the public),
each such time the Company will give written notice to all Holders of
outstanding Restricted Stock of its intention to do so. Upon the written request
of any such Holder received by the 

                                      -2-
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Company within 30 days of the giving of any such notice by the Company to
register any of such Holder's Restricted Stock (which request shall state the
intended method of disposition thereof), the Company will use its reasonable
best efforts to cause the Restricted Stock as to which registration shall have
been so requested to be included in the securities to be covered by the
registration statement proposed to be filed by the Company, all to the extent
requisite to permit the sale or other disposition by the Holder (in accordance
with such Holder's written request) of such Restricted Stock so registered. In
the event that any registration pursuant to this Section 4 shall be, in whole or
in part, an underwritten public offering of Common Stock, the number of shares
of Restricted Stock to be included in such an underwriting may be reduced if and
to the extent that the managing underwriter shall be of the opinion that such
inclusion would adversely affect the marketing of the securities to be sold by
the Company or the requesting party therein or that such reduction is otherwise
advisable, provided, however, any such reduction shall be accomplished as
follows: as among the requesting Holders and any other holders of securities of
the Company who have exercised their contractual rights to have shares included
in such registration, pro rata based upon the number of shares of Common Stock
owned by or issuable to such requesting Holders and other requesting holders,
unless such registration is pursuant to the exercise of a demand right of
another securityholder, in which event such securityholder shall be entitled to
include all shares it desires to have so included before any shares of
Restricted Stock or shares of any other holder are included therein.

           5.  Registration Procedures. If and whenever the Company is required
               -----------------------
by the provisions of Section 4 to use its reasonable best efforts to effect the
registration of any shares of Restricted Stock under the Securities Act, the
Company will, as expeditiously as possible:

           (a) prepare and file with the Commission a registration statement
with respect to such securities and use its reasonable best efforts to cause
such registration statement to become and remain effective for the period of the
distribution contemplated thereby (determined as hereinafter provided);

           (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration statement effective for
the period specified in paragraph (a) above and comply with the provisions of
the Securities Act with respect to the disposition of all Restricted Stock
covered by such registration statement in accordance with the sellers' intended
method of disposition set forth in such registration statement for such period;

           (c) furnish to each seller of Restricted Stock and to each
underwriter such number of copies of the registration statement and the
prospectus included therein (including each preliminary prospectus) as such
persons reasonably may request in order to facilitate the public sale or other
disposition of the Restricted Stock covered by such registration statement;

           (d) use its reasonable best efforts to register or qualify the
Restricted Stock covered by such registration statement under the securities or
"blue sky" laws of such jurisdictions as the sellers of Restricted Stock or, in
the case of an underwritten public offering, the managing 

                                      -3-
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underwriter reasonably shall request, provided, however, that the Company shall
                                      --------  -------
not for any such purpose be required to qualify generally to transact business
as a foreign corporation in any jurisdiction where it is not so qualified or to
consent to general service of process in any such jurisdiction;

           (e) use its reasonable best efforts to list the Restricted Stock
covered by such registration statement with any securities exchange on which the
Common Stock is then listed;

           (f) immediately notify each seller of Restricted Stock and each
underwriter under such registration statement, at any time when a prospectus
relating thereto is required to be delivered under the Securities Act, of the
happening of any event of which the Company has knowledge as a result of which
the prospectus contained in such registration statement, as then in effect,
includes an untrue statement of a material fact or omits to state a material
fact required to be stated therein or necessary to make the statements therein
not misleading in light of the circumstances then existing;

           (g) if the offering is underwritten and at the request of any seller
of Restricted Stock as provided herein, use its reasonable best efforts to
furnish on the date that Restricted Stock is delivered to the underwriters for
sale pursuant to such registration: (i) an opinion dated such date of counsel
representing the Company for the purposes of such registration, addressed to the
underwriters and to such seller, stating that such registration statement has
become effective under the Securities Act and that (A) to the knowledge of such
counsel, no stop order suspending the effectiveness thereof has been issued and
no proceedings for that purpose have been instituted or are pending or
threatened under the Securities Act, (B) the registration statement, the related
prospectus and each amendment or supplement thereof comply as to form in all
material respects with the requirements of the Securities Act (except that such
counsel need not express any opinion as to financial statements, schedules and
other financial or statistical information contained therein) and (C) to such
other effects as reasonably may be requested by counsel for the underwriters or
by such seller or its counsel and (ii) a letter dated such date from the
independent public accountants retained by the Company, addressed to the
underwriters and to such seller, stating that they are independent public
accountants within the meaning of the Securities Act and that, in the opinion of
such accountants, the financial statements of the Company included in the
registration statement or the prospectus, or any amendment or supplement
thereof, comply as to form in all material respects with the applicable
accounting requirements of the Securities Act, and such letter shall
additionally cover such other financial matters (including information as to the
period ending no more than five business days prior to the date of such letter)
with respect to such registration as such underwriters reasonably may request;
and

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           (h) make available for inspection by each seller of Restricted Stock,
any underwriter participating in any distribution pursuant to such registration
statement, and any attorney, accountant or other agent retained by such seller
or underwriter, all financial and other records, pertinent corporate documents
and properties of the Company, and cause the Company's officers, directors and
employees to supply all information reasonably requested by any such seller,
underwriter, attorney, accountant or agent in connection with such registration
statement.

           For purposes of Section 5(a) and 5(b), the period of distribution of
Restricted Stock included therein shall be deemed to extend until the first to
occur of (i) each underwriter's completion the distribution of all securities
purchased by it, and (ii) one hundred and twenty (120) days.

           In connection with each registration hereunder, the sellers of
Restricted Stock will furnish to the Company in writing such information with
respect to themselves and the proposed distribution by them as reasonably shall
be necessary in order to assure compliance with federal and applicable state
securities laws.

           In connection with each registration pursuant to Section 4 covering
an underwritten public offering, the Company and each seller agree to enter into
a written agreement with the managing underwriter selected in the manner herein
provided in such form and containing such provisions as are customary in the
securities business for such an arrangement between such underwriter and
companies of the Company's size and investment stature.

           No Holder of shares of Restricted Stock included in a registration
statement shall (until further notice) effect sales thereof after receipt of
telegraphic or written notice from the Company to suspend sales to permit the
Company to correct or update a registration statement or prospectus; but the
obligations of the Company with respect to maintaining any registration
statement current and effective shall be extended by a period of days equal to
the period such suspension is in effect unless (i) such extension would result
in the Company's inability to use the financial statements in the registration
statement as initially filed and (ii) such correction or update did not result
from the Company's acts or failures to act.

           At the end of the period during which the Company is obligated to
keep the registration statement current and effective as described above (and
any extensions thereof required by the preceding sentence), the Holders of
shares of Restricted Stock included in the registration statement shall
discontinue sales of shares pursuant to such registration statement upon receipt
of notice from the Company of its intention to remove from registration the
shares covered by such registration statement which remain unsold, and such
Holders shall notify the Company of the number of shares registered which remain
unsold immediately upon receipt of such notice from the Company.

           6.  Expenses. All expenses incurred by the Company in complying with
               --------
Section 4 including, without limitation, all registration and filing fees,
printing expenses, fees and disbursements of counsel to the Company and
independent public accountants for the Company, 

                                      -5-
<PAGE>
 
fees and expenses (including counsel fees) incurred in connection with complying
with state securities or "blue sky" laws, fees of the National Association of
Securities Dealers, Inc., transfer taxes, fees of transfer agents and
registrars, costs of insurance, shall be borne by the Company, except that all
expenses, fees and disbursements of any counsel retained by the Holders (to be
paid pro rata according to the quantity of the securities registered by the
Holders who retained such counsel, or as shall be otherwise agreed by such
Holders) and all underwriting discounts and commissions for securities
registered for sale by them shall be borne by the Holders of the securities
registered pursuant to such registration, pro rata according to the quantity of
their securities so registered.

           7.  Indemnification and Contribution.
               --------------------------------

           (a) To the extent permitted by law, in the event of a registration of
any of the Restricted Stock under the Securities Act pursuant to Section 4, the
Company will indemnify and hold harmless each seller of such Restricted Stock
thereunder, each underwriter of such Restricted Stock thereunder and each other
person, if any, who controls such seller or underwriter within the meaning of
the Securities Act, against any losses, claims, damages or liabilities, joint or
several, to which such seller, underwriter or controlling person may become
subject under the Securities Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon any untrue statement or alleged untrue statement of any material fact
contained in any registration statement under which such Restricted Stock was
registered under the Securities Act pursuant to Section 4, any preliminary
prospectus or final prospectus contained therein, or any amendment or supplement
thereof, or arise out of or are based upon the omission or alleged omission to
state therein a material fact required to be stated therein or necessary to make
the statements therein not misleading in the light of the circumstances in which
they were made, or arise out of any violation by the Company of any rule or
regulation promulgated under the Securities Act applicable to the Company and
relating to action or inaction required of the Company in connection with such
registration and will reimburse each such seller, each such underwriter and each
such controlling person for any legal or other expenses reasonably incurred by
them in connection with investigating or defending any such loss, claim, damage,
liability or action, provided, however, that the Company will not be liable in
any such case if and to the extent that any such loss, claim, damage or
liability arises out of or is based upon an untrue statement or alleged untrue
statement or omission or alleged omission so made in conformity with information
furnished by any such seller, any such underwriter or any such controlling
person in writing specifically for use in such registration statement or
prospectus, and except that the foregoing indemnity agreement is subject to the
condition that, insofar as it relates to any such untrue statement or alleged
untrue statement or omission or alleged omission made in the preliminary
prospectus but eliminated or remedied in the amended prospectus on file with the
Commission at the time the registration statement becomes effective or in the
amended prospectus filed with the Commission pursuant to Rule 424(b) or in the
prospectus subject to completion and term sheet under Rule 434 of the Securities
Act, which together meet the requirements of Section 10(a) of the Securities Act
(the "Final Prospectus"), such indemnity agreement shall not inure to the
benefit of any such seller, any such underwriter or any such controlling person,
if a copy of the Final Prospectus was not furnished to the person or 

                                      -6-
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entity asserting the loss, liability, claim or damage at or prior to the time
such furnishing is required by the Securities Act; provided, further, that this
                                                   --------  -------
indemnity shall not be deemed to relieve any underwriter of any of its due
diligence obligations.

        (b)     To the extent permitted by law, in the event of a registration
of any of the Restricted Stock under the Securities Act pursuant to Section 4,
each seller of such Restricted Stock thereunder, severally and not jointly, will
indemnify and hold harmless the Company, each person, if any, who controls the
Company within the meaning of the Securities Act, each officer of the Company
who signs the registration statement, each director of the Company, each
underwriter and each person who controls any underwriter within the meaning of
the Securities Act, against all losses, claims, damages or liabilities, joint or
several, to which the Company or such officer, director, underwriter or
controlling person may become subject under the Securities Act or otherwise,
insofar as such losses, claims, damages or liabilities (or actions in respect
thereof) arise out of or are based upon any untrue statement or alleged untrue
statement of any material fact contained in any registration statement under
which such Restricted Stock was registered under the Securities Act pursuant to
Section 4, any preliminary prospectus or final prospectus contained therein, or
any amendment or supplement thereof, or arise out of or are based upon the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading in the
light of the circumstances in which they were made, and will reimburse the
Company and each such officer, director, underwriter or controlling person for
any legal or other expenses reasonably incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action,
provided, however, that such seller will be liable hereunder in any such case if
and only to the extent that any such loss, claim, damage or liability arises out
of or is based upon an untrue statement or alleged untrue statement or omission
or alleged omission so made in reliance upon and in conformity with information
pertaining to such seller furnished in writing to the Company by such seller
specifically for use in such registration statement or prospectus, and provided,
further, that the foregoing indemnity agreement is subject to the condition
that, insofar as it relates to any such untrue statement or alleged untrue
statement or omission or alleged omission made in the preliminary prospectus but
eliminated or remedied in the amended prospectus on file with the Commission at
the time the registration statement becomes effective or in the Final
Prospectus, such indemnity agreement shall not inure to the benefit of the
Company, any controlling person or any underwriter, if a copy of the Final
Prospectus was not furnished to the person or entity asserting the loss,
liability, claim or damage at or prior to the time such furnishing is required
by the Securities Act; provided, further, that this indemnity shall not be
                       --------  -------
deemed to relieve any underwriter of any of its due diligence obligations; and
provided, further, that in no event shall any indemnity by a seller under this
--------  -------
Section 7(b) exceed the gross proceeds from the offering received by such
seller.

        (c)     Promptly after receipt by an indemnified party hereunder of
notice of the commencement of any action, such indemnified party shall, if a
claim in respect thereof is to be made against the indemnifying party hereunder,
notify the indemnifying party in writing thereof, but the omission so to notify
the indemnifying party shall not relieve it from 

                                      -7-
<PAGE>
 
any liability which it may have to such indemnified party other than under this
Section 7 and shall only relieve it from any liability which it may have to such
indemnified party under this Section 7 if and to the extent the indemnifying
party is prejudiced by such omission. In case any such action shall be brought
against any indemnified party and it shall notify the indemnifying party of the
commencement thereof, the indemnifying party shall be entitled to participate in
and, to the extent it shall wish, to assume and undertake the defense thereof
with counsel satisfactory to such indemnified party, and, after notice from the
indemnifying party to such indemnified party of its election so to assume and
undertake the defense thereof, the indemnifying party shall not be liable to
such indemnified party under this Section 7 for any legal expenses subsequently
incurred by such indemnified party in connection with the defense thereof other
than reasonable costs of investigation and of liaison with counsel so selected,
provided, however, that, if the defendants in any such action include both the
--------  -------
indemnified party and the indemnifying party and counsel to the indemnified
party shall have reasonably concluded that there are reasonable defenses
available to the indemnified party which are different from or additional to
those available to the indemnifying party or if the interests of the indemnified
party reasonably may be deemed to conflict with the interests of the
indemnifying party, the indemnified party shall have the right to select a
separate counsel and to assume such legal defenses and otherwise to participate
in the defense of such action, with the expenses and fees of such separate
counsel and other expenses related to such participation to be reimbursed by the
indemnifying party as incurred. No indemnifying party, in the defense of any
such claim or litigation, shall, except with the consent of each indemnified
party, consent to entry of any judgment or enter into any settlement which does
not include as an unconditional term thereof the giving by the claimant or
plaintiff to such indemnified party of a release from all liability in respect
to such claim or litigation.

        (d)     In order to provide for just and equitable contribution to joint
liability under the Securities Act in any case in which either (i) any Holder of
Restricted Stock exercising rights under this Agreement, or any controlling
person of any such Holder, makes a claim for indemnification pursuant to this
Section 7 but it is judicially determined (by the entry of a final judgment or
decree by a court of competent jurisdiction and the expiration of time to appeal
or the denial of the last right of appeal) that such indemnification may not be
enforced in such case notwithstanding the fact that this Section 7 provides for
indemnification in such case, or (ii) contribution under the Securities Act may
be required on the part of any such selling Holder or any such controlling
person in circumstances for which indemnification is provided under this Section
7; then, and in each such case, the Company and such Holder will contribute to
the aggregate losses, claims, damages or liabilities to which they may be
subject (after contribution from others) in such proportion so that such Holder
is responsible for the portion represented by the percentage that the public
offering price of its Restricted Stock offered by the registration statement
bears to the public offering price of all securities offered by such
registration statement, and the Company is responsible for the remaining
portion; provided, however, that, in any such case, (A) no such Holder will be
         --------  -------
required to contribute any amount in excess of the public offering price of all
such Restricted Stock offered by it pursuant to such registration statement; and
(B) no person or entity guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Securities Act) will be entitled to contribution
from any person or entity who was not guilty of such fraudulent
misrepresentation.

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        8.      Changes in Common Stock. If, and as often as, there is any
                -----------------------
change in the Common Stock by way of a stock split, stock dividend, combination
or reclassification, or through a merger, consolidation, reorganization or
recapitalization, or by any other means, appropriate adjustment shall be made in
the provisions hereof so that the rights and privileges granted hereby shall
continue with respect to the Common Stock as so changed.

        9.      Rule 144 Reporting. With a view to making available the benefits
                ------------------
of certain rules and regulations of the Commission which may at any time permit
the sale of the Restricted Stock to the public without registration, the Company
agrees to:
        
        (a)     make and keep public information available, as those terms are
understood and defined in Rule 144 under the Securities Act;

        (b)     use its reasonable best efforts to file with the Commission in a
timely manner all reports and other documents required of the Company under the
Securities Act and the Exchange Act; and

        (c)     furnish to each Holder of Restricted Stock forthwith upon
request a written statement by the Company as to its compliance with the
reporting requirements of such Rule 144 and of the Securities Act and the
Exchange Act, a copy of the most recent annual or quarterly report of the
Company, and such other reports and documents so filed by the Company as such
Holder may reasonably request in availing itself of any rule or regulation of
the Commission allowing such Holder to sell any Restricted Stock without
registration.

        The Company shall not be required to effect a registration pursuant to
Section 4 hereof for any Holder desiring to participate in such registration who
may then dispose of all of its shares of Restricted Stock pursuant to Rule 144
within the three-month period following such proposed registration.

        10.     Miscellaneous.
                -------------
        
        (a)     All covenants and agreements contained in this Agreement by or
on behalf of any of the parties hereto shall bind and inure to the benefit of
the respective successors and assigns of the parties hereto (including without
limitation transferees of any of the shares of Restricted Stock), whether so
expressed or not, provided, however, that registration rights conferred herein
on the Holders of shares of Restricted Stock shall only inure to the benefit of
a transferee of shares of Restricted Stock if such transferee, in the Company's
reasonable judgment, is not a competitor of the Company, and (i) there is
transferred to such transferee at least 20% of the total shares of Restricted
Stock originally issued to the direct or indirect transferor of such transferee
by the Company or (ii) such transfer is made in connection with the distribution
by a Holder to such Holder's beneficial owners (including, without limitation,
to partners of a general or limited partnership, shareholders of a corporation
and beneficiaries of a trust) of securities of the Holder or to the partners or
employees of the Holder, provided that at the Company's request, one person
shall be designated by such transferees as their agent for purposes of their
rights hereunder and 

                                      -9-
<PAGE>
 
the provision of a notice by the Company to such agent in accordance with the
provisions hereof shall be deemed compliance with such provisions for all such
beneficial owners, partners and employees, and following such request by the
Company, the Company shall have no obligation under said provisions with respect
to such transferees until it shall have been notified of the name and address of
such agent.

        (b)     Each Holder agrees that it will provide notice to the Company of
any transfer or assignment of its rights or interests hereunder. Any failure by
the Company to fulfill a covenant or obligation hereunder which is the direct
result of a failure by a Holder to provide such notice shall not be deemed to be
a breach of any covenant or obligation hereunder.

        Nothing in this Agreement shall be construed to create any rights or
obligations except among the parties hereto and their respective and permitted
successors and assigns, and no person or entity shall be regarded as a
third-party beneficiary of this Agreement.

        Except as provided in Section 10(a) above, all notices, requests,
consents and other communications hereunder shall be in writing, shall be
addressed to the receiving party's address set forth below or to such other
address as a party may designate by notice hereunder, and shall be either (i)
delivered by hand, (ii) sent by overnight courier, with a receipt obtained or
(iii) sent by registered or certified mail, return receipt requested, postage
prepaid.

If to the Company:             Occupational Health + Rehabilitation Inc
                               175 Derby Street, Suite 36
                               Hingham, MA 02043-5048
                               Attn:    John C. Garbarino, President and
                                        Chief Executive Officer

If to the Holder:              Argosy Health, L.P.
                               120 Gibraltar Road, Suite 310
                               Horsham, PA 19044
                               Attn: G. Linton Sheppard

        All notices, requests, consents and other communications hereunder shall
be deemed to have been given (i) if by hand, at the time of the delivery thereof
to the receiving party at the address of such party set forth above, (ii) if
sent by overnight courier, on the next business day following the day such
notice is delivered to the courier service, or (iii) if sent by registered or
certified mail, on the 5th business day following the day such mailing is made.

        (c) This Agreement shall be governed and construed in accordance with
the law of the Commonwealth of Massachusetts, without giving effect to the
conflict of laws principles thereof.

        (d) This Agreement may be amended or modified, and any provision hereof
may be waived in whole or in part, but only by the written consent of the
Company and the holders of at 

                                      -10-
<PAGE>
 
least two-thirds of the aggregate number of outstanding shares of Restricted
Stock held of record by the Holders or their permitted successors and assigns.
This Agreement may be terminated by written agreement of the Company and the
holders of at least two-thirds of the aggregate number of outstanding shares of
Restricted Stock held of record by the Holders or their permitted successors and
assigns.

        (e) This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

        (f) Except as otherwise expressly provided herein, the obligations of
the Company to register shares of Restricted Stock under Section 4 as provided
herein shall terminate on the third anniversary of the date of this Agreement.

        (g) If requested by the underwriter or underwriters for an underwritten
public offering of securities of the Company which offering is by the Company,
each Holder of Restricted Stock who is a party to this Agreement (including,
without limitation, a successor or permitted assignee of a party) shall agree
not to sell, make any short sale of, loan, grant any option for the purchase of,
or otherwise dispose of any shares of Restricted Stock or any other shares of
Common Stock (other than shares being registered in such offering), without the
consent of such underwriter or underwriters, for a period of not more than 90
days following the effective date of the registration statement relating to such
offering (unless in any event such underwriter or underwriters shall, based on
then current market conditions, agree to a shorter period), provided, however,
with respect to each such offering, that all persons entitled to registration
rights in such offering who are not parties to this Agreement, all other persons
selling shares of Common Stock in such offering and all executive officers of
the Company shall also have agreed to be bound by provisions pertaining to the
sale of their shares of Common Stock following such offering which provisions
are substantially similar to the provisions binding upon the Holders of
Restricted Stock obligated under this Agreement with respect to the sale of
their shares following such offering.

        (h) The Company shall be permitted to require any Holders requesting
registration under Section 4 to delay any request for registration or to cease
sales under any effective registration statement if the Company is then
contemplating a transaction that could reasonably be expected to be adversely
affected or the Company would be required to make public disclosure of
information, the disclosure of which at such time could reasonably be expected
to cause a material adverse effect upon the Company's business.

        (i) If any provision of this Agreement shall be held to be illegal,
invalid or unenforceable, such illegality, invalidity or unenforceability shall
attach only to such provision and shall not in any manner affect or render
illegal, invalid or unenforceable any other provision of this Agreement, and
this Agreement shall be carried out as if any such illegal, invalid or
unenforceable provision were not contained herein.

        In the event that any court of competent jurisdiction shall determine
that any provision, or any portion thereof, contained in this Agreement shall be
unreasonable or unenforceable in any 

                                      -11-
<PAGE>
 
respect, then such provision shall be deemed limited to the extent that such
court deems it reasonable and enforceable, and as so limited shall remain in
full force and effect.

        (j)     The headings and captions of the various subdivisions of this
Agreement are for convenience of reference only and shall in no way modify, or
affect the meaning or construction of any of the terms or provisions hereof.

        11.     Entire Agreement. This Agreement embodies the entire agreement
                ----------------
and understanding among the parties hereto with respect to the subject matter
hereof and supersedes all prior oral or written agreements and understandings
related to the subject matter hereof.

        IN WITNESS WHEREOF, the parties hereof have caused this Registration
Rights Agreement to be executed under seal as of the date first above written.

                                             OCCUPATIONAL HEALTH +
                                             REHABILITATION INC

                                             By:
                                                ---------------------------
                                                  John C. Garbarino
                                                  Its President and
                                                  Chief Executive Officer

                                              ARGOSY HEALTH, L.P.
                                              By: Gwynedd Partners, Inc.

                                                  By:
                                                     -----------------------   
                                                  Name:
                                                       ---------------------
                                                  Title:
                                                        --------------------

                                      -12-