<PAGE>
 
      As filed with the Securities and Exchange Commission on May 31, 1996

                                                      Registration No. 333-
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                                  AKSYS, LTD.
             (Exact name of registrant as specified in its charter)


          Delaware                                             36-3890205
(State or other jurisdiction of                             (I.R.S. Employer
incorporation or organization)                           Identification Number)
 
    1113 S. Milwaukee Ave, Suite 300                              60048
     Libertyville, Illinois  60048                             (Zip Code)
(Address of Principal Executive Offices)

                                  AKSYS, LTD.
                          EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                              LAWRENCE H. N. KINET
                      Chairman and Chief Executive Officer
                                  Aksys, Ltd.
                        1113 S. Milwaukee Ave, Suite 300
                         Libertyville, Illinois  60048
                    (Name and address of agent for service)

                                 (847) 247-6050
         (Telephone number, including area code, of agent for service)

                                    Copy to:
                                Mark Tresnowski
                                Kirkland & Ellis
                            200 East Randolph Drive
                            Chicago, Illinois 60601
                                 (312) 861-2000

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------
                                             Proposed maximum          Amount of
Title of securities to    Amount to be   aggregate offering price   registration fee 
    be registered          registered               (1)                   (1)
- ------------------------------------------------------------------------------------
<S>                       <C>            <C>                        <C>
Common Stock, par           200,000              
 value $0.01 per share      shares             $3,550,000.00           $1,224.14
- ------------------------------------------------------------------------------------
</TABLE>

(1)  The aggregate offering price and the amount of the registration fee have
     been computed in accordance with Rule 457(h) based on the average of the
     high and low prices of the shares reported in the consolidated reporting
     system on May 31, 1996.
<PAGE>
 
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

          The documents containing information specified in Part I (plan
information and registrant information) will be sent or given to employees as
specified by Rule 428 under the Securities Act of 1933, as amended (the
"Securities Act"). Such documents need not be filed with the Commission either
as part of this Registration Statement or as prospectuses or prospectus
supplements pursuant to Rule 424 under the Securities Act. These documents and
the documents incorporated by reference in this Registration Statement pursuant
to Item 3 of Part II of this Registration Statement, taken together, constitute
a prospectus that meets the requirements of Section 10(a) of the Securities Act.

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

          The following documents filed by Aksys, Ltd. (the "Corporation") with
the Securities and Exchange Commission (the "Commission") are incorporated
herein by reference:

     (a) The Prospectus of the Corporation, dated May 16, 1996, filed with the
Commission on May 17, 1996 pursuant to Rule 424(b) of the Securities Act
relating to the public offering of 3,565,000 shares of the Common Stock of the
Corporation, par value $0.01 per share (the "Common Stock"); and

     (b) Description of Common Stock contained in the Registration Statement of
the Corporation on Form 8-A filed with the Commission April 24, 1996.

          All reports and other documents subsequently filed by the Corporation
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934, as amended (the "Exchange Act") prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference herein and to be a part hereof from the date of the
filing of such reports and 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
incorporated or deemed to be incorporated by reference herein modifies or
supersedes such statement.  Any such 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 General Corporation Law of the State of Delaware,
as amended, permits indemnification of directors, officers, employees and agents
of corporations under certain conditions and subject to certain limitations. The
Restated Certificate of Incorporation, as amended, and the Amended and Restated
Bylaws of the Corporation provide for the indemnification of directors,
officers, employees and agents of the Corporation to the fullest extent
permitted by Section 145.

                                      -2-
<PAGE>
 
          The Corporation has obtained insurance policies under which its
directors and officers are insured, within the limits and subject to the
limitations of the policies, against certain expenses in connection with the
defense of certain actions, suits or proceedings and certain liabilities which
might be imposed as a result of certain actions, suits or proceedings, to which
they are parties by reason of being or having been such directors or officers.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

          Not applicable.

ITEM 8.  EXHIBITS.

          See Exhibit Index.
 
ITEM 9.  UNDERTAKINGS.

     (a) The Corporation 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;

               (ii)   to reflect in the prospectus any facts or events arising 
                      after the effective date of this 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 this
                      Registration Statement; and

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

          provided, however, that paragraphs (a)(1)(i) and (a)(1)(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 by the Corporation
pursuant to Section 13 or Section 15(d) of the Exchange Act that are
incorporated by reference in this Registration Statement.

          (2) 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.

          (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.

                                      -3-
<PAGE>
 
     (b) The Corporation hereby undertakes that, for purposes of determining any
liability under the Securities Act, each filing of the Corporation's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to 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 herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Corporation pursuant to the foregoing provisions, or otherwise, the Corporation
has been advised that in the opinion of the 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 Corporation of expenses incurred or
paid by a director, officer or controlling person of the Corporation 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 Corporation 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 Securities Act and will be governed by
the final adjudication of such issue.

                                      -4-

<PAGE>
 
                                   SIGNATURES

          Pursuant to the requirements of the Securities Act of 1933, as
amended, the Corporation 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 Libertyville, State of Illinois, on May 31, 1996.

                                    AKSYS, LTD.

                                    By: /s/  Lawrence H.N. Kinet
                                        -------------------------------------
                                        Lawrence H.N. Kinet
                                        Chairman and Chief Executive Officer


          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed by the following persons in
the capacities indicated on May 31, 1996.

<TABLE>
<CAPTION>
 
SIGNATURE                                   CAPACITY
- ---------                                  ---------
<S>                                         <C>
 
 /s/   LAWRENCE H.N. KINET       Chairman, Chief Executive Officer and Director
- -------------------------------
       Lawrence H.N. Kinet

 /s/   RODNEY S. KENLEY          President, Chief Operating Officer and Director
- -------------------------------
       Rodney S. Kenley

 /s/   DENNIS N. CAVENDER        Vice President, Chief Financial Officer
- -------------------------------
       Dennis N. Cavender

              *                  Director
- -------------------------------
       Peter H. McNerney

              *                  Director
- -------------------------------
       Larry G. Gerdes

              *                  Director
- -------------------------------
       W. Dekle Rountree, Jr.

 /s/   BERNARD R. TRESNOWSKI     Director
- -------------------------------
       Bernard R. Tresnowski
 
 
 
*By:  /s/   LAWRENCE H.N. KINET
     --------------------------
            Lawrence H.N. Kinet
            Attorney-in-fact
</TABLE>

                                      -5-
<PAGE>
 
                                 EXHIBIT INDEX
<TABLE>
<CAPTION>
 
 
Exhibit                                                          Sequentially
Number     Description of Document                               Numbered Page
- -------  ------------------------------------------------------  -------------
<C>      <S>                                                     <C>
  4.1    Restated Certificate of Incorporation of the 
         Corporation, incorporated by reference to the 
         Corporation's Registration Statement on Form S-1 
         (Registration No. 333-2492) (the "Registration 
         Statement"), Exhibit 3.1

  4.2    Amended and Restated Bylaws of the Corporation, 
         incorporated by reference to the Registration 
         Statement, Exhibit 3.2

  4.3    Employee Stock Purchase Plan

  5      Opinion of Kirkland & Ellis

  23.1   Consent of KPMG Peat Marwick LLP

  23.2   Consent of Kirkland & Ellis (included in Exhibit 5)

  99     Power of Attorney (included in Part II of the 
         Registration Statement)
</TABLE>

                                      -6-
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 14165}]
{"company-data": {"conformed-name": "AKSYS LTD", "cik": "0000902600", "assigned-sic": "3841", "irs-number": "363890205", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-04945", "film-number": "96575654"}, "business-address": {"street1": "1113 S MILWAUKEE AVE", "street2": "STE 300", "city": "LIBERTYVILLE", "state": "IL", "zip": "60048", "phone": "8472476051"}, "mail-address": {"street1": "1113 S MILWAUKEE AVE", "street2": "SUITE 300", "city": "LIBERTYVILLE", "state": "IL", "zip": "60048"}}
As filed with the Securities and Exchange Commission on May 31, 1996

                                                      Registration No. 333-
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                                  AKSYS, LTD.
             (Exact name of registrant as specified in its charter)

          Delaware                                             36-3890205
(State or other jurisdiction of                             (I.R.S. Employer
incorporation or organization)                           Identification Number)
 
    1113 S. Milwaukee Ave, Suite 300                              60048
     Libertyville, Illinois  60048                             (Zip Code)
(Address of Principal Executive Offices)

                                  AKSYS, LTD.
                          EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                              LAWRENCE H. N. KINET
                      Chairman and Chief Executive Officer
                                  Aksys, Ltd.
                        1113 S. Milwaukee Ave, Suite 300
                         Libertyville, Illinois  60048
                    (Name and address of agent for service)

                                 (847) 247-6050
         (Telephone number, including area code, of agent for service)

                                    Copy to:
                                Mark Tresnowski
                                Kirkland & Ellis
                            200 East Randolph Drive
                            Chicago, Illinois 60601
                                 (312) 861-2000

                        CALCULATION OF REGISTRATION FEE
- ------------------------------------------------------------------------------------
                                             Proposed maximum          Amount of
Title of securities to    Amount to be   aggregate offering price   registration fee 
    be registered          registered               (1)                   (1)
- ------------------------------------------------------------------------------------
Common Stock, par           200,000              
 value $0.01 per share      shares             $3,550,000.00           $1,224.14
- ------------------------------------------------------------------------------------
(1)  The aggregate offering price and the amount of the registration fee have
     been computed in accordance with Rule 457(h) based on the average of the
     high and low prices of the shares reported in the consolidated reporting
     system on May 31, 1996.
PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

          The documents containing information specified in Part I (plan
information and registrant information) will be sent or given to employees as
specified by Rule 428 under the Securities Act of 1933, as amended (the
"Securities Act"). Such documents need not be filed with the Commission either
as part of this Registration Statement or as prospectuses or prospectus
supplements pursuant to Rule 424 under the Securities Act. These documents and
the documents incorporated by reference in this Registration Statement pursuant
to Item 3 of Part II of this Registration Statement, taken together, constitute
a prospectus that meets the requirements of Section 10(a) of the Securities Act.

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

          The following documents filed by Aksys, Ltd. (the "Corporation") with
the Securities and Exchange Commission (the "Commission") are incorporated
herein by reference:

     (a) The Prospectus of the Corporation, dated May 16, 1996, filed with the
Commission on May 17, 1996 pursuant to Rule 424(b) of the Securities Act
relating to the public offering of 3,565,000 shares of the Common Stock of the
Corporation, par value $0.01 per share (the "Common Stock"); and

     (b) Description of Common Stock contained in the Registration Statement of
the Corporation on Form 8-A filed with the Commission April 24, 1996.

          All reports and other documents subsequently filed by the Corporation
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934, as amended (the "Exchange Act") prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference herein and to be a part hereof from the date of the
filing of such reports and 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
incorporated or deemed to be incorporated by reference herein modifies or
supersedes such statement.  Any such 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 General Corporation Law of the State of Delaware,
as amended, permits indemnification of directors, officers, employees and agents
of corporations under certain conditions and subject to certain limitations. The
Restated Certificate of Incorporation, as amended, and the Amended and Restated
Bylaws of the Corporation provide for the indemnification of directors,
officers, employees and agents of the Corporation to the fullest extent
permitted by Section 145.

                                      -2-
The Corporation has obtained insurance policies under which its
directors and officers are insured, within the limits and subject to the
limitations of the policies, against certain expenses in connection with the
defense of certain actions, suits or proceedings and certain liabilities which
might be imposed as a result of certain actions, suits or proceedings, to which
they are parties by reason of being or having been such directors or officers.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

          Not applicable.

ITEM 8.  EXHIBITS.

          See Exhibit Index.
 
ITEM 9.  UNDERTAKINGS.

     (a) The Corporation 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;

               (ii)   to reflect in the prospectus any facts or events arising 
                      after the effective date of this 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 this
                      Registration Statement; and

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

          provided, however, that paragraphs (a)(1)(i) and (a)(1)(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 by the Corporation
pursuant to Section 13 or Section 15(d) of the Exchange Act that are
incorporated by reference in this Registration Statement.

          (2) 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.

          (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.

                                      -3-
(b) The Corporation hereby undertakes that, for purposes of determining any
liability under the Securities Act, each filing of the Corporation's annual
report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to 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 herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Corporation pursuant to the foregoing provisions, or otherwise, the Corporation
has been advised that in the opinion of the 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 Corporation of expenses incurred or
paid by a director, officer or controlling person of the Corporation 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 Corporation 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 Securities Act and will be governed by
the final adjudication of such issue.

                                      -4-
SIGNATURES

          Pursuant to the requirements of the Securities Act of 1933, as
amended, the Corporation 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 Libertyville, State of Illinois, on May 31, 1996.

                                    AKSYS, LTD.

                                    By: /s/  Lawrence H.N. Kinet
                                        -------------------------------------
                                        Lawrence H.N. Kinet
                                        Chairman and Chief Executive Officer

          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed by the following persons in
the capacities indicated on May 31, 1996.
SIGNATURE                                   CAPACITY
- ---------                                  ---------
/s/   LAWRENCE H.N. KINET       Chairman, Chief Executive Officer and Director
- -------------------------------
       Lawrence H.N. Kinet

 /s/   RODNEY S. KENLEY          President, Chief Operating Officer and Director
- -------------------------------
       Rodney S. Kenley

 /s/   DENNIS N. CAVENDER        Vice President, Chief Financial Officer
- -------------------------------
       Dennis N. Cavender

              *                  Director
- -------------------------------
       Peter H. McNerney

              *                  Director
- -------------------------------
       Larry G. Gerdes

              *                  Director
- -------------------------------
       W. Dekle Rountree, Jr.

 /s/   BERNARD R. TRESNOWSKI     Director
- -------------------------------
       Bernard R. Tresnowski
 
 
 
*By:  /s/   LAWRENCE H.N. KINET
     --------------------------
            Lawrence H.N. Kinet
            Attorney-in-fact
-5-
EXHIBIT INDEX
Exhibit                                                          Sequentially
Number     Description of Document                               Numbered Page
- -------  ------------------------------------------------------  -------------
4.1    Restated Certificate of Incorporation of the 
         Corporation, incorporated by reference to the 
         Corporation's Registration Statement on Form S-1 
         (Registration No. 333-2492) (the "Registration 
         Statement"), Exhibit 3.1

  4.2    Amended and Restated Bylaws of the Corporation, 
         incorporated by reference to the Registration 
         Statement, Exhibit 3.2

  4.3    Employee Stock Purchase Plan

  5      Opinion of Kirkland & Ellis

  23.1   Consent of KPMG Peat Marwick LLP

  23.2   Consent of Kirkland & Ellis (included in Exhibit 5)

  99     Power of Attorney (included in Part II of the 
         Registration Statement)
-6-