<PAGE>

     As filed with the Securities and Exchange Commission on April 5, 2001
                                                     Registration No. 333-


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                                  SEPRACOR INC.
             (Exact Name of Registrant as Specified in Its Charter)


          DELAWARE                                               22-2536587
(State or Other Jurisdiction of                              (I.R.S. Employer
Incorporation or Organization)                              Identification No.)


                111 LOCKE DRIVE, MARLBOROUGH, MASSACHUSETTS 01752
               (Address of Principal Executive Offices) (Zip Code)


                            2000 STOCK INCENTIVE PLAN
                            (Full Title of the Plan)


                              SUSAN W. MURLEY, ESQ.
                                HALE AND DORR LLP
                                 60 STATE STREET
                           BOSTON, MASSACHUSETTS 02109
                     (Name and Address of Agent For Service)

                                 (617) 526-6000
          (Telephone Number, Including Area Code, of Agent For Service)

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>

--------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------
 Title of securities to        Amount to be        Proposed maximum      Proposed maximum           Amount of
      be registered             registered        offering price per    aggregate offering      registration fee
                                                         share                 price
<S>                          <C>                 <C>                  <C>                      <C>

--------------------------------------------------------------------------------------------------------------------
Common Stock,                 2,500,000 shares       $ 30.0(1)             $75,000,000(1)           $18,750
$.10 par value
--------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)      Estimated solely for the purpose of calculating the registration fee,
         and based upon the average of the high and low prices of the Common
         Stock on the Nasdaq National Market on April 4, 2001 in accordance
         with Rules 457(c) and 457(h) of the Securities Act of 1933.

<PAGE>

PART I.  INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         Item 1. PLAN INFORMATION
                 ----------------

         The information required by Item I is included in documents sent or
given to participants in the 2000 Stock Incentive Plan of Sepracor Inc., a
Delaware corporation (the "Registrant"), pursuant to Rule 428(b)(1) under the
Securities Act of 1933, as amended (the "Securities Act").

         Item 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION
                 -----------------------------------------------------------

         The written statement required by Item 2 is included in documents
sent or given to participants in the 2000 Stock Incentive Plan of the
Registrant pursuant to Rule 428(b)(1) of the Securities Act.

PART II. INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Item 3. INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.
                 -----------------------------------------------

         The Registrant is subject to the informational and reporting
requirements of Sections 13(a), 14, and 15(d) of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and in accordance therewith
files reports, proxy statements and other information with the Securities and
Exchange Commission (the "Commission"). The following documents, which are
filed with the Commission, are incorporated in this Registration Statement by
reference:

         (1) The Registrant's latest annual report filed pursuant to Section
         13(a) or 15(d) of the Exchange Act, or the latest prospectus filed
         pursuant to Rule 424(b) under the Securities Act, that contains audited
         financial statements for the Registrant's latest fiscal year for which
         such statements have been filed.

         (2) All other reports filed pursuant to Section 13(a) or 15(d) of the
         Exchange Act since the end of the fiscal year covered by the document
         referred to in (1) above.

         (3) The description of the Common Stock, par value $.10 per share
         ("Common Stock"), contained in a registration statement filed under the
         Exchange Act, including any amendment or report filed for the purpose
         of updating such description.

         All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14, and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all shares of Common Stock
offered hereby have been sold or which deregisters all shares of Common Stock
then remaining unsold, shall be deemed to be incorporated by reference herein
and to be part hereof from the date of the 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 the
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 statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this
Registration Statement.

         Item 4. DESCRIPTION OF SECURITIES.
                 -------------------------

         Not applicable.

         Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.
                 --------------------------------------

         Not applicable.

         Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
                 -----------------------------------------

         Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify any person who was or is a party or is threatened to
be made a party to any threatened, pending or completed action or proceeding,
whether civil, criminal, administrative or investigative, by reason of the fact
that he is or was a director, officer, employee or agent of the corporation or
is or was serving at its request in such capacity in another corporation or
business

                                      -2-
<PAGE>

association, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by him in connection
with such action, suit or proceeding if he acted in good faith and in a manner
he reasonably believed to be in or not opposed to the best interests of the
corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.

         Section 102(b)(7) of the Delaware General Corporation Law permits a
corporation to provide in its certificate of incorporation that a director of
the corporation shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the Delaware General Corporation Law, or (iv) for any transaction
from which the director derived an improper personal benefit.

         Article NINTH of the Registrant's Restated Certificate of
Incorporation, as amended, (the "Certificate of Incorporation") provides that no
director of the Registrant shall be liable for any breach of a fiduciary duty,
except to the extent that the Delaware General Corporation Law prohibits the
elimination or limitation of liability of directors for breach of fiduciary
duty.

         Article THIRTEENTH of the Certificate of Incorporation provides that a
director or officer of the Registrant (a) shall be indemnified by the Registrant
against all costs, charges, expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement incurred in connection with any litigation
or other legal proceeding (other than an action by or in the right of the
Registrant) brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and, with respect to any criminal action or proceeding, has no
reasonable cause to believe his conduct was unlawful and (b) shall be
indemnified by the Registrant against all costs, charges and expenses (including
attorneys' fees) incurred in connection with any action by or in the right of
the Registrant brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, except that no indemnification shall be made with respect to any
such matter as to which such person shall have been adjudged to be liable to the
Registrant, unless a court determines that, despite such adjudication but in
view of all of the circumstances, he is entitled to indemnification of such
expenses. Notwithstanding the foregoing, to the extent that a director or
officer has been successful, on the merits or otherwise, including, without
limitation, the dismissal of an action without prejudice or the settlement of an
action without admission of liability, he is required to be indemnified by the
Registrant against all costs, charges and expenses (including attorneys' fees)
incurred in connection therewith. Expenses shall be advanced to a director or
officer at his request, provided that he undertakes to repay the amount advanced
if it is ultimately determined that the is not entitled to indemnification for
such expenses.

         Indemnification is required to be made unless the Board of Directors or
independent legal counsel determines that the applicable standard of conduct
required for indemnification has not been met. In the event of a determination
by the Board of Directors or independent legal counsel that the director or
officer did not meet the applicable standard of conduct required for
indemnification, or if the Registrant fails to make the applicable standard of
conduct required for

                                      -3-
<PAGE>

indemnification, or if the Registrant fails to make an indemnification payment
within 60 days after such payment is claimed by such person, such person is
permitted to petition the court to make an independent determination as to
whether such person is entitled to indemnification. As a condition precedent to
the right of indemnification, the director or officer must give the Registrant
notice of the action for which indemnity is sought and the Registrant has the
right to participate in such action or assume the defense thereto.

         Article THIRTEENTH of the Certificate of Incorporation further provides
that the indemnification provided therein is not exclusive, and provides that in
the event that the Delaware General Corporation Law is amended to expand the
indemnification permitted to directors or officers the Registrant must indemnify
those persons to the fullest extent permitted by such law as so amended.

         Item 7. EXEMPTION FROM REGISTRATION CLAIMED.
                 -----------------------------------

         Not applicable.

         Item 8. EXHIBITS.
                 --------

         The Exhibit Index immediately preceding the exhibits is incorporated
herein by reference.

         Item 9. UNDERTAKINGS.
                 ------------

         1.       The Registrant hereby undertakes:

                  (a) 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;

                           (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;
                           and

                                      -4-
<PAGE>

                           (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 (a)(i) and (a)(ii) do not apply if
         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 that are incorporated by reference
         in the Registration Statement.

                  (b) That, for the purpose of determining any liability under
                  the Securities Act, 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.

                  (c) 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.

         2. The Registrant hereby undertakes that, for the purposes of
determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act 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 in the initial BONA FIDE offering thereof.

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


                                      -5-
<PAGE>

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act, the Registrant
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 town of Marlborough, Commonwealth of Massachusetts, on the
5th day of April, 2001.

                                         SEPRACOR INC.


                                         By: /s/ Robert F. Scumaci
                                             -----------------------------
                                             Robert F. Scumaci,
                                             Executive Vice President, Finance
                                             and Administration, and Treasurer



                                POWER OF ATTORNEY

         We, the undersigned officers and directors of Sepracor Inc. hereby
severally constitute Timothy J. Barberich, David P. Southwell and Robert F.
Scumaci, and each of them singly, our true and lawful attorneys with full
power to them, and each of them singly, to sign for us and in our names in
the capacities indicated below, the Registration Statement on Form S-8 filed
herewith and any and all subsequent amendments to said Registration
Statement, and generally to do all such things in our names and behalf in our
capacities as officers and directors to enable Sepracor Inc. to comply with
the provisions of the Securities Act of 1933, as amended, and all
requirements of the Securities and Exchange Commission, hereby ratifying and
confirming our signatures as they may be signed by said attorneys, or any of
them, to said Registration Statement and any and all amendments thereto.

                                      -6-
<PAGE>


         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the date indicated.

<TABLE>
<CAPTION>

 SIGNATURE                                     TITLE                                     DATE
<S>                                          <C>                                       <C>

/s/ Timothy J. Barberich
-------------------------                      Chief Executive Officer and               April 5, 2001
 Timothy J. Barberich                          Director (Principal Executive
                                               Officer)

/s/ David P. Southwell
-------------------------                      Executive Vice President and              April 5, 2001
 David P. Southwell                            Chief Financial Officer
                                               (Principal Financial Officer)

/s/ Robert F. Scumaci
-------------------------                      Executive Vice President, Finance         April 5, 2001
 Robert F. Scumaci                             and Administration (Principal
                                               Accounting Officer)

/s/ James G. Andress
-------------------------                      Director                                  April 5, 2001
 James G. Andress

/s/ Digby W. Barrios
-------------------------                      Director                                  April 5, 2001
 Digby W. Barrios

/s/ Robert J. Cresci
-------------------------                      Director                                  April 5, 2001
 Robert J. Cresci

/s/ Keith Mansford, Ph.D.
-------------------------                      Director                                  April 5, 2001
 Keith Mansford, Ph.D.

/s/ James F. Mrazek
-------------------------                      Director                                  April 5, 2001
 James F. Mrazek

/s/ Alan A. Steigrod
-------------------------                      Director                                  April 5, 2001
 Alan A. Steigrod

</TABLE>


                                      -7-
<PAGE>


                                  EXHIBIT INDEX

EXHIBIT
NUMBER      DESCRIPTION

4.1(1)      Restated Certificate of Incorporation of the Registrant, as amended
4.2(1)      Amended and Restated By-Laws of the Registrant
4.3(2)      Specimen Certificate of Common Stock of the Registrant
5           Opinion of Hale and Dorr LLP
23.1        Consent of Hale and Dorr LLP (included in Exhibit 5)
23.2        Consent of PricewaterhouseCoopers LLP
23.3        Consent of Arthur Andersen LLP
24          Power of Attorney (included in the signature pages of this
            Registration Statement)


------------------------

(1)      Incorporated herein by reference from the Registrant's Annual Report on
         Form 10-K for the year ended December 31, 2000.

(2)      Incorporated herein by reference from the Registrant's Registration
         Statement on Form S-1 (File No. 33-41653).


                                      -8-
[{"type": "S-8", "sequence": "1", "filename": "a2040195zs-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 21383}]
{"company-data": {"conformed-name": "SEPRACOR INC /DE/", "cik": "0000877357", "assigned-sic": "2834", "irs-number": "222536587", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-58368", "film-number": "1596513"}, "business-address": {"street1": "111 LOCKE DR", "city": "MARLBOROUGH", "state": "MA", "zip": "01757", "phone": "5084816700"}}
As filed with the Securities and Exchange Commission on April 5, 2001
                                                     Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                                  SEPRACOR INC.
             (Exact Name of Registrant as Specified in Its Charter)

          DELAWARE                                               22-2536587
(State or Other Jurisdiction of                              (I.R.S. Employer
Incorporation or Organization)                              Identification No.)

                111 LOCKE DRIVE, MARLBOROUGH, MASSACHUSETTS 01752
               (Address of Principal Executive Offices) (Zip Code)

                            2000 STOCK INCENTIVE PLAN
                            (Full Title of the Plan)

                              SUSAN W. MURLEY, ESQ.
                                HALE AND DORR LLP
                                 60 STATE STREET
                           BOSTON, MASSACHUSETTS 02109
                     (Name and Address of Agent For Service)

                                 (617) 526-6000
          (Telephone Number, Including Area Code, of Agent For Service)

                         CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------
 Title of securities to        Amount to be        Proposed maximum      Proposed maximum           Amount of
      be registered             registered        offering price per    aggregate offering      registration fee
                                                         share                 price
--------------------------------------------------------------------------------------------------------------------
Common Stock,                 2,500,000 shares       $ 30.0(1)             $75,000,000(1)           $18,750
$.10 par value
--------------------------------------------------------------------------------------------------------------------
(1)      Estimated solely for the purpose of calculating the registration fee,
         and based upon the average of the high and low prices of the Common
         Stock on the Nasdaq National Market on April 4, 2001 in accordance
         with Rules 457(c) and 457(h) of the Securities Act of 1933.
PART I.  INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         Item 1. PLAN INFORMATION
                 ----------------

         The information required by Item I is included in documents sent or
given to participants in the 2000 Stock Incentive Plan of Sepracor Inc., a
Delaware corporation (the "Registrant"), pursuant to Rule 428(b)(1) under the
Securities Act of 1933, as amended (the "Securities Act").

         Item 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION
                 -----------------------------------------------------------

         The written statement required by Item 2 is included in documents
sent or given to participants in the 2000 Stock Incentive Plan of the
Registrant pursuant to Rule 428(b)(1) of the Securities Act.

PART II. INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Item 3. INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.
                 -----------------------------------------------

         The Registrant is subject to the informational and reporting
requirements of Sections 13(a), 14, and 15(d) of the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and in accordance therewith
files reports, proxy statements and other information with the Securities and
Exchange Commission (the "Commission"). The following documents, which are
filed with the Commission, are incorporated in this Registration Statement by
reference:

         (1) The Registrant's latest annual report filed pursuant to Section
         13(a) or 15(d) of the Exchange Act, or the latest prospectus filed
         pursuant to Rule 424(b) under the Securities Act, that contains audited
         financial statements for the Registrant's latest fiscal year for which
         such statements have been filed.

         (2) All other reports filed pursuant to Section 13(a) or 15(d) of the
         Exchange Act since the end of the fiscal year covered by the document
         referred to in (1) above.

         (3) The description of the Common Stock, par value $.10 per share
         ("Common Stock"), contained in a registration statement filed under the
         Exchange Act, including any amendment or report filed for the purpose
         of updating such description.

         All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14, and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all shares of Common Stock
offered hereby have been sold or which deregisters all shares of Common Stock
then remaining unsold, shall be deemed to be incorporated by reference herein
and to be part hereof from the date of the 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 the
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 statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this
Registration Statement.

         Item 4. DESCRIPTION OF SECURITIES.
                 -------------------------

         Not applicable.

         Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.
                 --------------------------------------

         Not applicable.

         Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
                 -----------------------------------------

         Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify any person who was or is a party or is threatened to
be made a party to any threatened, pending or completed action or proceeding,
whether civil, criminal, administrative or investigative, by reason of the fact
that he is or was a director, officer, employee or agent of the corporation or
is or was serving at its request in such capacity in another corporation or
business

                                      -2-
association, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by him in connection
with such action, suit or proceeding if he acted in good faith and in a manner
he reasonably believed to be in or not opposed to the best interests of the
corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.

         Section 102(b)(7) of the Delaware General Corporation Law permits a
corporation to provide in its certificate of incorporation that a director of
the corporation shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the Delaware General Corporation Law, or (iv) for any transaction
from which the director derived an improper personal benefit.

         Article NINTH of the Registrant's Restated Certificate of
Incorporation, as amended, (the "Certificate of Incorporation") provides that no
director of the Registrant shall be liable for any breach of a fiduciary duty,
except to the extent that the Delaware General Corporation Law prohibits the
elimination or limitation of liability of directors for breach of fiduciary
duty.

         Article THIRTEENTH of the Certificate of Incorporation provides that a
director or officer of the Registrant (a) shall be indemnified by the Registrant
against all costs, charges, expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement incurred in connection with any litigation
or other legal proceeding (other than an action by or in the right of the
Registrant) brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and, with respect to any criminal action or proceeding, has no
reasonable cause to believe his conduct was unlawful and (b) shall be
indemnified by the Registrant against all costs, charges and expenses (including
attorneys' fees) incurred in connection with any action by or in the right of
the Registrant brought against him by virtue of his position as a director or
officer of the Registrant if he acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, except that no indemnification shall be made with respect to any
such matter as to which such person shall have been adjudged to be liable to the
Registrant, unless a court determines that, despite such adjudication but in
view of all of the circumstances, he is entitled to indemnification of such
expenses. Notwithstanding the foregoing, to the extent that a director or
officer has been successful, on the merits or otherwise, including, without
limitation, the dismissal of an action without prejudice or the settlement of an
action without admission of liability, he is required to be indemnified by the
Registrant against all costs, charges and expenses (including attorneys' fees)
incurred in connection therewith. Expenses shall be advanced to a director or
officer at his request, provided that he undertakes to repay the amount advanced
if it is ultimately determined that the is not entitled to indemnification for
such expenses.

         Indemnification is required to be made unless the Board of Directors or
independent legal counsel determines that the applicable standard of conduct
required for indemnification has not been met. In the event of a determination
by the Board of Directors or independent legal counsel that the director or
officer did not meet the applicable standard of conduct required for
indemnification, or if the Registrant fails to make the applicable standard of
conduct required for

                                      -3-
indemnification, or if the Registrant fails to make an indemnification payment
within 60 days after such payment is claimed by such person, such person is
permitted to petition the court to make an independent determination as to
whether such person is entitled to indemnification. As a condition precedent to
the right of indemnification, the director or officer must give the Registrant
notice of the action for which indemnity is sought and the Registrant has the
right to participate in such action or assume the defense thereto.

         Article THIRTEENTH of the Certificate of Incorporation further provides
that the indemnification provided therein is not exclusive, and provides that in
the event that the Delaware General Corporation Law is amended to expand the
indemnification permitted to directors or officers the Registrant must indemnify
those persons to the fullest extent permitted by such law as so amended.

         Item 7. EXEMPTION FROM REGISTRATION CLAIMED.
                 -----------------------------------

         Not applicable.

         Item 8. EXHIBITS.
                 --------

         The Exhibit Index immediately preceding the exhibits is incorporated
herein by reference.

         Item 9. UNDERTAKINGS.
                 ------------

         1.       The Registrant hereby undertakes:

                  (a) 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;

                           (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;
                           and

                                      -4-
(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 (a)(i) and (a)(ii) do not apply if
         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 that are incorporated by reference
         in the Registration Statement.

                  (b) That, for the purpose of determining any liability under
                  the Securities Act, 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.

                  (c) 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.

         2. The Registrant hereby undertakes that, for the purposes of
determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act 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 in the initial BONA FIDE offering thereof.

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

                                      -5-
SIGNATURES

         Pursuant to the requirements of the Securities Act, the Registrant
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 town of Marlborough, Commonwealth of Massachusetts, on the
5th day of April, 2001.

                                         SEPRACOR INC.

                                         By: /s/ Robert F. Scumaci
                                             -----------------------------
                                             Robert F. Scumaci,
                                             Executive Vice President, Finance
                                             and Administration, and Treasurer

                                POWER OF ATTORNEY

         We, the undersigned officers and directors of Sepracor Inc. hereby
severally constitute Timothy J. Barberich, David P. Southwell and Robert F.
Scumaci, and each of them singly, our true and lawful attorneys with full
power to them, and each of them singly, to sign for us and in our names in
the capacities indicated below, the Registration Statement on Form S-8 filed
herewith and any and all subsequent amendments to said Registration
Statement, and generally to do all such things in our names and behalf in our
capacities as officers and directors to enable Sepracor Inc. to comply with
the provisions of the Securities Act of 1933, as amended, and all
requirements of the Securities and Exchange Commission, hereby ratifying and
confirming our signatures as they may be signed by said attorneys, or any of
them, to said Registration Statement and any and all amendments thereto.

                                      -6-
Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the date indicated.
SIGNATURE                                     TITLE                                     DATE
/s/ Timothy J. Barberich
-------------------------                      Chief Executive Officer and               April 5, 2001
 Timothy J. Barberich                          Director (Principal Executive
                                               Officer)

/s/ David P. Southwell
-------------------------                      Executive Vice President and              April 5, 2001
 David P. Southwell                            Chief Financial Officer
                                               (Principal Financial Officer)

/s/ Robert F. Scumaci
-------------------------                      Executive Vice President, Finance         April 5, 2001
 Robert F. Scumaci                             and Administration (Principal
                                               Accounting Officer)

/s/ James G. Andress
-------------------------                      Director                                  April 5, 2001
 James G. Andress

/s/ Digby W. Barrios
-------------------------                      Director                                  April 5, 2001
 Digby W. Barrios

/s/ Robert J. Cresci
-------------------------                      Director                                  April 5, 2001
 Robert J. Cresci

/s/ Keith Mansford, Ph.D.
-------------------------                      Director                                  April 5, 2001
 Keith Mansford, Ph.D.

/s/ James F. Mrazek
-------------------------                      Director                                  April 5, 2001
 James F. Mrazek

/s/ Alan A. Steigrod
-------------------------                      Director                                  April 5, 2001
 Alan A. Steigrod
-7-
EXHIBIT INDEX

EXHIBIT
NUMBER      DESCRIPTION

4.1(1)      Restated Certificate of Incorporation of the Registrant, as amended
4.2(1)      Amended and Restated By-Laws of the Registrant
4.3(2)      Specimen Certificate of Common Stock of the Registrant
5           Opinion of Hale and Dorr LLP
23.1        Consent of Hale and Dorr LLP (included in Exhibit 5)
23.2        Consent of PricewaterhouseCoopers LLP
23.3        Consent of Arthur Andersen LLP
24          Power of Attorney (included in the signature pages of this
            Registration Statement)

------------------------

(1)      Incorporated herein by reference from the Registrant's Annual Report on
         Form 10-K for the year ended December 31, 2000.

(2)      Incorporated herein by reference from the Registrant's Registration
         Statement on Form S-1 (File No. 33-41653).

                                      -8-