<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8


                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


                            CLINTRIALS RESEARCH INC.
--------------------------------------------------------------------------------
             (Exact Name of Registrant as Specified in its Charter)


                 Delaware                              62-1406017
   ---------------------------------       ---------------------------------
     (State or other jurisdiction                  (I.R.S. Employer
   of incorporation or organization)            Identification Number)


                              11000 Weston Parkway
                           Cary, North Carolina 27513
--------------------------------------------------------------------------------
                    (Address of Principal Executive Offices)
                                   (Zip Code)


   CLINTRIALS RESEARCH INC. 1998 NON-QUALIFIED STOCK OPTION PLAN FOR DIRECTORS
--------------------------------------------------------------------------------
                               (Full Name of Plan)


                         Jerry R. Mitchell, M.D., Ph.D.
          Chairman of the Board, President and Chief Executive Officer
                            ClinTrials Research Inc.
                              11000 Weston Parkway
                           Cary, North Carolina 27513
--------------------------------------------------------------------------------
                     (Name and Address of Agent for Service)


                                 (919) 460-9005
--------------------------------------------------------------------------------
          (Telephone number, including area code for agent for service)


                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
                                                            Proposed                    Proposed Maximum               Amount of
Title of Securities              Amount to be            Maximum Offering              Aggregate Offering             Registration
To be Registered                Registered(1)            Price Per Share(2)                  Price                         Fee
-------------------             -------------            ------------------            ------------------             ------------
<S>                             <C>                      <C>                           <C>                             <C>
Common Stock,                  200,000 Shares                  $4.31                      $862,000.00                     $227.57
$0.01 Par Value
-----------------------------------------------------------------------------------------------------------------------------------

</TABLE>

(1) In addition, pursuant to Rule 416(c) under the Securities Act of 1933
    as amended (the "Securities Act"), this registration statement also
    covers an indeterminate number of additional shares that may become
    issuable pursuant to the anti-dilution adjustment provisions of the
    Plan.

(2) Pursuant to Rule 457, the offering price is estimated solely for the
    purpose of calculating the registration fee on the basis of the average
    of the high and low prices for the Common Stock on the NASDAQ National
    Market System on March 17, 2000.


        The Index to Exhibits appears on sequentially numbered page II-8.





<PAGE>   2



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The documents listed below are incorporated by reference in this
Registration Statement. In addition, all documents subsequently filed by
ClinTrials Research Inc. (the "Company," the "Registrant" or "ClinTrials")
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934 (the "Exchange Act"), prior to the filing of a post-effective amendment
which indicates that all securities offered have been sold or which deregisters
all securities then remaining unsold, shall be deemed to be incorporated by
reference in this Registration Statement and to be a part hereof from the date
of filing of such documents. Any statement contained in a document incorporated
or deemed to be incorporated by reference herein shall be deemed to be modified
or superseded for purposes of this Registration Statement to the extent that a
statement contained herein or in any other subsequently filed document which
also is or is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such statement modified or superseded shall not
be deemed, except as so modified or superseded, to constitute a part of this
Registration Statement.

         (a) The Company's Annual Report on Form 10-K pursuant to the Securities
Exchange Act of 1934 for the fiscal year ended December 31, 1999 filed with
Securities and Exchange Commission (the "SEC") on February 28, 2000;

         (b) The description of the Company's shares of Common Stock, par value
$.01 per share (the "Common Stock"), contained in the Company's Registration
Statement on Form 8-A filed under Section 12 of the Exchange Act of 1934,
effective November 22, 1993.

ITEM 4.  DESCRIPTION OF SECURITIES

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not applicable.

ITEM 6.  INDEMNIFICATION.

         The Company's Restated Certificate of Incorporation, as amended to
date, provides for indemnification of directors and officers to the fullest
extent permitted by the Delaware Law. Specifically, no director of the Company
will be personally liable for any expense, liability or loss arising from any
alleged action or inaction in an official capacity as a director or officer or
in any other capacity while serving as a director or officer.

         Section 145 of the General Corporation Law of the state of Delaware
(the "Delaware Law") empowers a Delaware corporation to indemnify any persons
who are, or are threatened to be made, parties to any threatened, pending or
completed legal action, suit or proceeding whether civil, criminal,




                                      II-2

<PAGE>   3



administrative or investigative (other than an action by or in right of such
corporation), by reason of the fact that such person is or was an officer,
director, employee or agent of such corporation, or is or was serving at the
request of such corporation as a director, officer, employee or agent of another
corporation or enterprise. The indemnity may include expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding, provided that such officer or director acted in good faith and in a
manner he reasonably believed to be in or not opposed to the corporation's best
interest, and, for criminal proceedings, had no reasonable cause to believe his
conduct was unlawful. A Delaware corporation may indemnify officers, directors,
employees or agents in an action by or in the right of the corporation under the
same conditions, except that no indemnification is permitted without judicial
approval if the officer or director is adjudged to be liable to the corporation
in the performance of his duty. Where an officer, director, employee or agent is
successful on the merits or otherwise in the defense of any action referred to
above, the corporation must indemnify him against the expenses which such
officer or director actually or reasonably incurred.

         Under its Restated Certificate of Incorporation and in accordance with
Section 145 of the Delaware Law, the Company will indemnify any person who was
or is a party to or is threatened to be made a party to, or is involuntarily
involved in any action, suit or proceeding, whether civil, criminal,
administrative or investigative, by reason of the fact that such person is or
was a director or officer of the Company or is or was serving (during his or her
tenure as director and/or officer) at the request of the Company as a director,
officer, employee or agent of another corporation or of a partnership, joint
venture, trust or other enterprise, against all expense, liability and loss
(including attorneys' fees, judgments, fines, ERISA excise taxes or penalties
and amounts paid or to be paid in settlement) reasonably incurred or suffered by
such person in connection with such action, suit or proceeding.

         The Restated Certificate of Incorporation of the Company provides that
the Company will pay for the expenses incurred by an indemnified director or
officer in defending the proceedings specified above in advance of the final
disposition, provided that, if the Delaware Law (or other applicable law) so
requires, such person agrees to reimburse the Company if it is ultimately
determined that such person is not entitled to indemnification. The Company's
Restated Certificate of Incorporation also provides that the Company may, in its
sole discretion, indemnify any person who is or was one of its employees and
agents to the same degree as the foregoing indemnification of directors and
officers.

         In addition, the Restated Certificate of Incorporation of the Company
provides that the Company may purchase and maintain insurance on behalf of any
person who is or was a director, officer, employee or agent of the Company, or
is serving at the request of the Company as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise against any liability asserted against and incurred by such person in
such capacity, or arising out of such person's status as such whether or not the
Company would have the power or obligation to indemnify such person against such
liability under the provisions of the Delaware Law.

         The Company has entered into indemnification agreements with each of
its directors. Each such Indemnification Agreement provides for indemnification
to the fullest extent permitted by Delaware Law and additionally permits
advancement of expenses to such director. If it is later determined that the
director is not entitled to indemnification, the director agrees to reimburse
the Company for such expenses.

         Each Indemnification Agreement further provides that in the event of a
change in control of the Company, the determination of the director's rights to
indemnification and the director's standard of conduct,



                                      II-3

<PAGE>   4



as well as the evaluation of the reasonableness of amounts claimed by the
director, may be made by a special, independent counsel who is retained by the
director and approved by the Company (such approval not to be unreasonably
withheld) and who has not otherwise performed services for the director or the
Company.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

         Not applicable.

ITEM 8.  EXHIBITS.

         The Exhibits to this Registration Statement are listed in the Index to
Exhibits on Page II-8 of this Registration Statement, which Index is
incorporated herein by reference.








                                      II-4

<PAGE>   5



ITEM 9.  UNDERTAKINGS.

         The Company hereby undertakes:

         1. To file, during any period in which offers or sales are being made,
a post-effective amendment to this Registration Statement:

                  (i) To include any prospectus required by section 10(a)(3) of
the Securities Act of 1933;

                  (ii) To reflect in the prospectus any facts or events arising
after the effective date of the Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the Registration
Statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high and of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than 20 percent change in the
maximum aggregate offering price set forth in the "Calculation of Registration
Fee" table in the effective registration statement.

                  (iii) To include any material information with respect to the
plan of distribution not previously disclosed in the Registration Statement or
any material change to such information in the Registration Statement;

PROVIDED, HOWEVER, that paragraphs (1)(i) and (1)(ii) do not apply if the
registration statement is on Form S-3, Form S-8 or Form F-3 and the information
required to be included in a post-effective amendment by those paragraphs is
contained in periodic reports filed with or furnished to the Commission by the
registrant pursuant to Section 13 or Section 15(d) of the Exchange Act of 1934
that are incorporated by reference in the Registration Statement.

         2. That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         3. To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

         4. The Company hereby undertakes that, for purposes of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act of 1934
(and, where applicable, each filing of an employee benefit plan's annual report
pursuant to Section 15(d) of the Exchange Act of 1934) that is incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.



                                      II-5

<PAGE>   6



         5. Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to partners, directors, officers and
controlling persons of the Company pursuant to the foregoing provisions, or
otherwise, the Company has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Company of expenses incurred or paid by a partner, director, officer or
controlling person of the Company in the successful defense of any action suit
or proceeding) is asserted by such partner, director, officer or controlling
person in connection with the securities being registered, the Company will,
unless in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the Act and
will be governed by the final adjudication of such issue.




















                                      II-6

<PAGE>   7



                                   SIGNATURES



         Pursuant to the requirements of the Securities Act of 1933, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Cary, State of North Carolina, on March 17, 2000.


                                   ClinTrials Research Inc.

                                   By:  /s/ Jerry R. Mitchell, M.D., Ph.D.
                                       ----------------------------------------
                                   Name: Jerry R. Mitchell, M.D., Ph.D.
                                   Title: President of ClinTrials Research Inc.


         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.


<TABLE>
<CAPTION>

               SIGNATURE                                     Title                                 Date
               ---------                                     -----                                 ----


<S>                                    <C>                                                    <C>
/s/ Jerry R. Mitchell, M.D., Ph.D.     President, Chief Executive Officer and                 March 17, 2000
-----------------------------------    Chairman of the Board
Jerry R. Mitchell, M.D., Ph.D



/s/ S. Colin Neill                     Senior Vice President and Chief Financial              March 17, 2000
----------------------------------     Officer
S. Colin Neill



/s/ Irwin B. Eskind                    Director                                               March 17, 2000
----------------------------------
Irwin B. Eskind



/s/ Richard J. Eskind                  Director                                               March 17, 2000
----------------------------------
Richard J. Eskind



/s/ Edward G. Nelson                   Director                                               March 17, 2000
----------------------------------
Edward G. Nelson



/s/ Roscoe R. Robinson, M.D.           Director                                               March 17, 2000
----------------------------------
Roscoe R. Robinson, M.D.


</TABLE>


                                      II-7

<PAGE>   8



                                  EXHIBIT INDEX





            EXHIBIT NO.                      DESCRIPTION OF EXHIBIT
            -----------                      ----------------------

                4.1           Restated Certificate of Incorporation of the
                              Company, as amended (Incorporated by reference to
                              Exhibit 3.1 of the Company's Registration
                              Statement on Form S-1 No. 33-69568, filed with the
                              Securities and Exchange Commission under the
                              Securities Act of 1933, on September 29, 1993).

                4.2           Bylaws of the Company (Incorporated by reference
                              to Exhibit 3.2 of the Company's Registration
                              Statement on Form S-1 No. 33-69568, filed with
                              the Securities and Exchange Commission under the
                              Securities Act of 1933, on September 29, 1993).

                4.3           ClinTrials Research Inc. 1998 Non-Qualified Stock
                              Option Plan for Directors (Incorporated by
                              reference to Exhibit A of the Company's Definitive
                              Proxy Statement filed with the Securities and
                              Exchange Commission under the Securities Exchange
                              Act of 1934, on April 9, 1998).

                5.1           Opinion of Harwell Howard Hyne Gabbert & Manner,
                              P.C.

               23.1           Consent of Ernst & Young LLP, Independent Auditors

               23.2           Consent of Harwell Howard Hyne Gabbert & Manner,
                              P.C. (contained in Exhibit 5.1)






                                      II-8
[{"type": "S-8", "sequence": "1", "description": "CLINTRIALS RESEARCH INC.", "secsgml_size_bytes": 20253}]
{"company-data": {"conformed-name": "CLINTRIALS RESEARCH INC", "cik": "0000870978", "assigned-sic": "8734", "irs-number": "621406017", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-32918", "film-number": "574882"}, "business-address": {"street1": "11000 WESTON PARKWAY", "city": "CARY", "state": "NC", "zip": "27513", "phone": "9194622556"}, "mail-address": {"street1": "11000 WESTON PARKWAY", "city": "CARY", "state": "NC", "zip": "27513"}, "former-company": {"former-conformed-name": "CLINTRIALS INC", "date-changed": "19930930"}}
1
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                            CLINTRIALS RESEARCH INC.
--------------------------------------------------------------------------------
             (Exact Name of Registrant as Specified in its Charter)

                 Delaware                              62-1406017
   ---------------------------------       ---------------------------------
     (State or other jurisdiction                  (I.R.S. Employer
   of incorporation or organization)            Identification Number)

                              11000 Weston Parkway
                           Cary, North Carolina 27513
--------------------------------------------------------------------------------
                    (Address of Principal Executive Offices)
                                   (Zip Code)

   CLINTRIALS RESEARCH INC. 1998 NON-QUALIFIED STOCK OPTION PLAN FOR DIRECTORS
--------------------------------------------------------------------------------
                               (Full Name of Plan)

                         Jerry R. Mitchell, M.D., Ph.D.
          Chairman of the Board, President and Chief Executive Officer
                            ClinTrials Research Inc.
                              11000 Weston Parkway
                           Cary, North Carolina 27513
--------------------------------------------------------------------------------
                     (Name and Address of Agent for Service)

                                 (919) 460-9005
--------------------------------------------------------------------------------
          (Telephone number, including area code for agent for service)

                         CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
                                                            Proposed                    Proposed Maximum               Amount of
Title of Securities              Amount to be            Maximum Offering              Aggregate Offering             Registration
To be Registered                Registered(1)            Price Per Share(2)                  Price                         Fee
-------------------             -------------            ------------------            ------------------             ------------
Common Stock,                  200,000 Shares                  $4.31                      $862,000.00                     $227.57
$0.01 Par Value
-----------------------------------------------------------------------------------------------------------------------------------
(1) In addition, pursuant to Rule 416(c) under the Securities Act of 1933
    as amended (the "Securities Act"), this registration statement also
    covers an indeterminate number of additional shares that may become
    issuable pursuant to the anti-dilution adjustment provisions of the
    Plan.

(2) Pursuant to Rule 457, the offering price is estimated solely for the
    purpose of calculating the registration fee on the basis of the average
    of the high and low prices for the Common Stock on the NASDAQ National
    Market System on March 17, 2000.

        The Index to Exhibits appears on sequentially numbered page II-8.
2

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The documents listed below are incorporated by reference in this
Registration Statement. In addition, all documents subsequently filed by
ClinTrials Research Inc. (the "Company," the "Registrant" or "ClinTrials")
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934 (the "Exchange Act"), prior to the filing of a post-effective amendment
which indicates that all securities offered have been sold or which deregisters
all securities then remaining unsold, shall be deemed to be incorporated by
reference in this Registration Statement and to be a part hereof from the date
of filing of such documents. Any statement contained in a document incorporated
or deemed to be incorporated by reference herein shall be deemed to be modified
or superseded for purposes of this Registration Statement to the extent that a
statement contained herein or in any other subsequently filed document which
also is or is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such statement modified or superseded shall not
be deemed, except as so modified or superseded, to constitute a part of this
Registration Statement.

         (a) The Company's Annual Report on Form 10-K pursuant to the Securities
Exchange Act of 1934 for the fiscal year ended December 31, 1999 filed with
Securities and Exchange Commission (the "SEC") on February 28, 2000;

         (b) The description of the Company's shares of Common Stock, par value
$.01 per share (the "Common Stock"), contained in the Company's Registration
Statement on Form 8-A filed under Section 12 of the Exchange Act of 1934,
effective November 22, 1993.

ITEM 4.  DESCRIPTION OF SECURITIES

         Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

         Not applicable.

ITEM 6.  INDEMNIFICATION.

         The Company's Restated Certificate of Incorporation, as amended to
date, provides for indemnification of directors and officers to the fullest
extent permitted by the Delaware Law. Specifically, no director of the Company
will be personally liable for any expense, liability or loss arising from any
alleged action or inaction in an official capacity as a director or officer or
in any other capacity while serving as a director or officer.

         Section 145 of the General Corporation Law of the state of Delaware
(the "Delaware Law") empowers a Delaware corporation to indemnify any persons
who are, or are threatened to be made, parties to any threatened, pending or
completed legal action, suit or proceeding whether civil, criminal,

                                      II-2
3

administrative or investigative (other than an action by or in right of such
corporation), by reason of the fact that such person is or was an officer,
director, employee or agent of such corporation, or is or was serving at the
request of such corporation as a director, officer, employee or agent of another
corporation or enterprise. The indemnity may include expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by such person in connection with such action, suit or
proceeding, provided that such officer or director acted in good faith and in a
manner he reasonably believed to be in or not opposed to the corporation's best
interest, and, for criminal proceedings, had no reasonable cause to believe his
conduct was unlawful. A Delaware corporation may indemnify officers, directors,
employees or agents in an action by or in the right of the corporation under the
same conditions, except that no indemnification is permitted without judicial
approval if the officer or director is adjudged to be liable to the corporation
in the performance of his duty. Where an officer, director, employee or agent is
successful on the merits or otherwise in the defense of any action referred to
above, the corporation must indemnify him against the expenses which such
officer or director actually or reasonably incurred.

         Under its Restated Certificate of Incorporation and in accordance with
Section 145 of the Delaware Law, the Company will indemnify any person who was
or is a party to or is threatened to be made a party to, or is involuntarily
involved in any action, suit or proceeding, whether civil, criminal,
administrative or investigative, by reason of the fact that such person is or
was a director or officer of the Company or is or was serving (during his or her
tenure as director and/or officer) at the request of the Company as a director,
officer, employee or agent of another corporation or of a partnership, joint
venture, trust or other enterprise, against all expense, liability and loss
(including attorneys' fees, judgments, fines, ERISA excise taxes or penalties
and amounts paid or to be paid in settlement) reasonably incurred or suffered by
such person in connection with such action, suit or proceeding.

         The Restated Certificate of Incorporation of the Company provides that
the Company will pay for the expenses incurred by an indemnified director or
officer in defending the proceedings specified above in advance of the final
disposition, provided that, if the Delaware Law (or other applicable law) so
requires, such person agrees to reimburse the Company if it is ultimately
determined that such person is not entitled to indemnification. The Company's
Restated Certificate of Incorporation also provides that the Company may, in its
sole discretion, indemnify any person who is or was one of its employees and
agents to the same degree as the foregoing indemnification of directors and
officers.

         In addition, the Restated Certificate of Incorporation of the Company
provides that the Company may purchase and maintain insurance on behalf of any
person who is or was a director, officer, employee or agent of the Company, or
is serving at the request of the Company as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise against any liability asserted against and incurred by such person in
such capacity, or arising out of such person's status as such whether or not the
Company would have the power or obligation to indemnify such person against such
liability under the provisions of the Delaware Law.

         The Company has entered into indemnification agreements with each of
its directors. Each such Indemnification Agreement provides for indemnification
to the fullest extent permitted by Delaware Law and additionally permits
advancement of expenses to such director. If it is later determined that the
director is not entitled to indemnification, the director agrees to reimburse
the Company for such expenses.

         Each Indemnification Agreement further provides that in the event of a
change in control of the Company, the determination of the director's rights to
indemnification and the director's standard of conduct,

                                      II-3
4

as well as the evaluation of the reasonableness of amounts claimed by the
director, may be made by a special, independent counsel who is retained by the
director and approved by the Company (such approval not to be unreasonably
withheld) and who has not otherwise performed services for the director or the
Company.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

         Not applicable.

ITEM 8.  EXHIBITS.

         The Exhibits to this Registration Statement are listed in the Index to
Exhibits on Page II-8 of this Registration Statement, which Index is
incorporated herein by reference.

                                      II-4
5

ITEM 9.  UNDERTAKINGS.

         The Company hereby undertakes:

         1. To file, during any period in which offers or sales are being made,
a post-effective amendment to this Registration Statement:

                  (i) To include any prospectus required by section 10(a)(3) of
the Securities Act of 1933;

                  (ii) To reflect in the prospectus any facts or events arising
after the effective date of the Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the Registration
Statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high and of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than 20 percent change in the
maximum aggregate offering price set forth in the "Calculation of Registration
Fee" table in the effective registration statement.

                  (iii) To include any material information with respect to the
plan of distribution not previously disclosed in the Registration Statement or
any material change to such information in the Registration Statement;

PROVIDED, HOWEVER, that paragraphs (1)(i) and (1)(ii) do not apply if the
registration statement is on Form S-3, Form S-8 or Form F-3 and the information
required to be included in a post-effective amendment by those paragraphs is
contained in periodic reports filed with or furnished to the Commission by the
registrant pursuant to Section 13 or Section 15(d) of the Exchange Act of 1934
that are incorporated by reference in the Registration Statement.

         2. That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         3. To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

         4. The Company hereby undertakes that, for purposes of determining any
liability under the Securities Act of 1933, each filing of the Company's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act of 1934
(and, where applicable, each filing of an employee benefit plan's annual report
pursuant to Section 15(d) of the Exchange Act of 1934) that is incorporated by
reference in the Registration Statement shall be deemed to be a new registration
statement relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.

                                      II-5
6

         5. Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to partners, directors, officers and
controlling persons of the Company pursuant to the foregoing provisions, or
otherwise, the Company has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Company of expenses incurred or paid by a partner, director, officer or
controlling person of the Company in the successful defense of any action suit
or proceeding) is asserted by such partner, director, officer or controlling
person in connection with the securities being registered, the Company will,
unless in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the Act and
will be governed by the final adjudication of such issue.

                                      II-6
7

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Cary, State of North Carolina, on March 17, 2000.

                                   ClinTrials Research Inc.

                                   By:  /s/ Jerry R. Mitchell, M.D., Ph.D.
                                       ----------------------------------------
                                   Name: Jerry R. Mitchell, M.D., Ph.D.
                                   Title: President of ClinTrials Research Inc.

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.
SIGNATURE                                     Title                                 Date
               ---------                                     -----                                 ----
/s/ Jerry R. Mitchell, M.D., Ph.D.     President, Chief Executive Officer and                 March 17, 2000
-----------------------------------    Chairman of the Board
Jerry R. Mitchell, M.D., Ph.D

/s/ S. Colin Neill                     Senior Vice President and Chief Financial              March 17, 2000
----------------------------------     Officer
S. Colin Neill

/s/ Irwin B. Eskind                    Director                                               March 17, 2000
----------------------------------
Irwin B. Eskind

/s/ Richard J. Eskind                  Director                                               March 17, 2000
----------------------------------
Richard J. Eskind

/s/ Edward G. Nelson                   Director                                               March 17, 2000
----------------------------------
Edward G. Nelson

/s/ Roscoe R. Robinson, M.D.           Director                                               March 17, 2000
----------------------------------
Roscoe R. Robinson, M.D.
II-7
8

                                  EXHIBIT INDEX

            EXHIBIT NO.                      DESCRIPTION OF EXHIBIT
            -----------                      ----------------------

                4.1           Restated Certificate of Incorporation of the
                              Company, as amended (Incorporated by reference to
                              Exhibit 3.1 of the Company's Registration
                              Statement on Form S-1 No. 33-69568, filed with the
                              Securities and Exchange Commission under the
                              Securities Act of 1933, on September 29, 1993).

                4.2           Bylaws of the Company (Incorporated by reference
                              to Exhibit 3.2 of the Company's Registration
                              Statement on Form S-1 No. 33-69568, filed with
                              the Securities and Exchange Commission under the
                              Securities Act of 1933, on September 29, 1993).

                4.3           ClinTrials Research Inc. 1998 Non-Qualified Stock
                              Option Plan for Directors (Incorporated by
                              reference to Exhibit A of the Company's Definitive
                              Proxy Statement filed with the Securities and
                              Exchange Commission under the Securities Exchange
                              Act of 1934, on April 9, 1998).

                5.1           Opinion of Harwell Howard Hyne Gabbert & Manner,
                              P.C.

               23.1           Consent of Ernst & Young LLP, Independent Auditors

               23.2           Consent of Harwell Howard Hyne Gabbert & Manner,
                              P.C. (contained in Exhibit 5.1)

                                      II-8