As filed with the Securities and Exchange Commission on April 23, 1999
                                                      Registration No. 333-75071
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                 Amendment No. 1
                                       to
                                    FORM S-1
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                              --------------------

                                CareInsite, Inc.
             (Exact name of registrant as specified in its charter)

         Delaware                      7374                     22-3630930
(State or other jurisdiction     (Primary Standard           (I.R.S. Employer
     of incorporation         Industrial Classification   Identification Number)
     or organization)              Code Number)

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

                                CareInsite, Inc.
                     669 River Drive, River Drive Center II
                         Elmwood Park, New Jersey 07407
                                 (201) 703-3400
               (Address, including zip code, and telephone number,
            including area code, of registrant's principal executive
                                    offices)
                              --------------------

                                David C. Amburgey
                                CareInsite, Inc.
                        Vice President -- General Counsel
                     669 River Drive, River Drive Center II
                         Elmwood Park, New Jersey 07407
                                 (201) 703-3400
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                              --------------------

                                   Copies to:

    Stephen T. Giove                                        Alan J. Jakimo
   Shearman & Sterling                                     Brown & Wood LLP
  599 Lexington Avenue                                  One World Trade Center
New York, New York 10022                               New York, New York 10048
     (212) 848-4000                                         (212) 839-5300
                              --------------------

         Approximate date of commencement of proposed sale to the public: As
soon as practicable after this Registration Statement becomes effective.
         If any of the securities being registered on this Form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, check the following box. |_|
         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. |_|
         If this Form is a post-effective amendment filed pursuant to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier registration statement for the
same offering. |_|
         If this Form is a post-effective amendment filed pursuant to Rule
462(d) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier registration statement for the
same offering. |_|
         If delivery of the prospectus is expected to be made pursuant to Rule 
434 under the Securities Act, please check the following box.  |_|

         The Registrant hereby amends this Registration Statement on such date
or dates as may be necessary to delay its effective date until the Registrant
shall file a further amendment that specifically states that this Registration
Statement shall thereafter become effective in accordance with Section 8(a) of
the Securities Act of 1933, as amended, or until the Registration Statement
shall become effective on such date as the Commission, acting pursuant to said
Section 8(a), may determine.
================================================================================






                                EXPLANATORY NOTE

         This Amendment No. 1 is being filed solely for the purpose of amending
Item 16 of Part II of the Registration Statement (Registration No. 333-75071)
and the filing of certain exhibits. This Amendment No. 1 does not contain a copy
of the Prospectus included in the Registration Statement, which is unchanged
from the initial filing of the Registration Statement on March 26, 1999.






                                     PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

         SEC registration fee...................................... $  17,236
         NASD filing fee...........................................     6,700
         Nasdaq listing fee........................................        *
         Blue Sky fees and expenses................................        *
         Printing and engraving expenses...........................        *
         Attorneys' fees and expenses..............................        *
         Accountants' fees and expenses............................        *
         Transfer agent's and registrar's fees and expenses........        *
         Miscellaneous.............................................        *
                                                                      --------
                  Total............................................        *
                                                                      ========


- ------------------
* To be supplied by amendment

         The amounts set forth above are estimates except for the SEC
registration fee and the NASD filing fee.

ITEM 14.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware General Corporation Law provides, in
summary, that directors and officers of Delaware corporations are entitled,
under certain circumstances, to be indemnified against all expenses and
liabilities (including attorney's fees) incurred by them as a result of suits
brought against them in their capacity as a director or officer, if they acted
in good faith and in a manner they reasonably believed to be in or not opposed
to the best interests of the Company, and, with respect to any criminal action
or proceeding, if they had no reasonable cause to believe their conduct was
unlawful; provided that no indemnification may be made against expenses in
respect of any claim, issue or matter as to which they shall have been adjudged
to be liable to the Company, unless and only to the extent that the court in
which such action or suit was brought shall determine upon application that,
despite the adjudication of liability but in view of all the circumstances of
the case, they are fairly and reasonably entitled to indemnity for such expenses
which the court shall deem proper. Any such indemnification may be made by the
Company only as authorized in each specific case upon a determination by the
shareholders or disinterested directors that indemnification is proper because
the indemnities have met the applicable standard of conduct.

         Article Six of the registrant's Certificate of Incorporation provides
that no director of the registrant shall be personally liable to the Company 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 Company or its stockholders; (ii) for acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law; (iii) in respect of certain unlawful dividend payments or stock redemptions
or purchases; or (iv) for any transaction from which the director derived an
improper personal benefit.

         The Company's Certificate of Incorporation and By-Laws provide for
indemnification of its directors and officers to the fullest extent permitted by
Delaware law, as the same may be amended from time to time.

         In addition, the Company maintains liability insurance for its
directors and officers.









ITEM 15.  RECENT SALES OF UNREGISTERED SECURITIES.

         The following information reflects sales by the registrant of
unregistered securities within the past three years. The issuance by the
registrant of the securities sold in the transactions referenced below were not
registered under the Securities Act of 1933, as amended pursuant to Section 4(2)
thereof, as such transactions did not involve a public offering.

         In January 1999, the registrant issued to The Health Information
Network Connection LLC (i) a warrant (the "THINC Warrant") exercisable for
1,298,917 shares of the registrant's common stock (subject to adjustment),
representing approximately 6% of the registrant's common stock outstanding after
giving effect to the exercise of the THINC Warrant and (ii) $1.5 million in
cash, in exchange for a 20% ownership interest in THINC.

         In January 1999, the registrant issued to Cerner Corporation (i)
3,980,000 shares of its common stock, representing 19.9% of its common stock
outstanding after such issuance, and (ii) a warrant exercisable for a number of
shares of common stock of the registrant equal to 19.9% of the shares issuable
upon exercise of the THINC Warrant, each in consideration for Cerner Corporation
entering into non-competition, marketing, license and master servicing and
outsourcing agreements with the registrant.

ITEM 16.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

         (a)      Exhibits.

         Exhibit
         Number                             Description of Exhibit
         ------                             ----------------------

         1.1               Form of Underwriting Agreement.*
         3.1               Amended and Restated Certificate of Incorporation of 
                           the Registrant.*
         3.2               By-laws of the Registrant.*
         4.1               Specimen Certificate representing Common Stock.*
         5.1               Opinion of Shearman & Sterling as to the legality of 
                           the Common Stock.*
         10.1              Agreement and Plan of Merger among Synetic, Inc., 
                           Synternet Acquisition Corp., a subsidiary of Synetic,
                           Inc., Avicenna Systems Corp., and the individuals and
                           entities listed on the signature pages thereof, dated
                           as of December 23, 1996.*
         10.2              Agreement and Plan of Merger among Synetic, Inc.,
                           Synternet Acquisition Corp., CareAgents Inc. and the
                           individuals listed on the signature pages thereof,
                           dated as of January 23, 1997.*
         10.3              Subscription Agreement dated as of January 2, 1999
                           between Synetic Healthcare Communications, Inc.
                           ("SHC"), Synetic, Inc., Avicenna Systems Corporation
                           and Cerner Corporation.*
         10.4              License Agreement dated as of January 2, 1999 between
                           SHC and Cerner Corporation.*
         10.5              Stockholders' Agreement, dated as of January 2, 1999,
                           among SHC, Synetic, Inc., Avicenna Systems
                           Corporation and Cerner Corporation.*
         10.6              Non-Competition Agreement, dated as of January 2,
                           1999, among SHC, Synetic, Inc., Avicenna Systems
                           Corporation and Cerner Corporation.*
         10.7              Marketing Agreement, dated as of January 2, 1999,
                           between SHC and Cerner Corporation.*
         10.8              Clinical Transaction Agreement, dated as of January
                           1, 1999, between SHC and Empire Blue Cross and Blue
                           Shield, Empire Healthchoice, Inc., Empire
                           Healthchoice Assurance Inc. and Empire Health Plans
                           Assurance, Inc.+
         10.9              Clinical Transaction Agreement, dated as of January
                           1, 1999, between SHC and Group Health Incorporated.+
         10.10             Clinical Transaction Agreement, dated as of January
                           1, 1999, between SHC and Health Insurance Plans of
                           Greater New York.+

                                      II-2





         10.11             Management Services Agreement, effective as of
                           January 1, 1999, between SHC and The Health
                           Information Network Connection LLC ("THINC").*
         10.12             Warrant dated as of January 1, 1999 (entitling THINC
                           to purchase from SHC 81,081 shares of common stock).*
         10.13             Amended and Restated Operating Agreement, dated as of
                           January 1, 1999, among The Health Information Network
                           Connection LLC, Empire Blue Cross and Blue Shield,
                           GNYHA Management Corporation, Group Health
                           Incorporated, Health Insurance Plan of Greater New
                           York and SHC.*
         10.14             Form of Tax-Sharing Agreement between the Registrant
                           and Synetic, Inc.*
         10.15             Form of Services Agreement between the Registrant and
                           Synetic, Inc.*
         10.16             CareInsite, Inc. Stock Option Plan.*
         23.1              Consent of Arthur Andersen LLP.**
         23.2              Consent of Shearman & Sterling (included in its
                           opinion in Exhibit 5.1).
         23.3              Consent of Kegler, Brown, Hill & Ritter Co., L.P.A.**
         24.1              Powers of Attorney (included on the signature page of
                           this Registration Statement).**
         27.1              Financial Data Schedule for fiscal year ended June
                           30, 1998 (for SEC use only).**
         27.2              Financial Data Schedule for six months ended December
                           31, 1998 (for SEC use only).**

- -------------------
*        To be filed by amendment.
**       Previously filed.
+        Exhibits for which Registrant is seeking confidential treatment for
         certain portions. Confidential material has been redacted and has been
         separately filed with the Securities and Exchange Commission.

         (b)      Financial Statement Schedules.

         The schedules have been omitted because of the absence of circumstances
under which they would be required.

ITEM 17.  UNDERTAKINGS

Insofar as indemnification for liabilities arising under the Securities Act of
1933 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 of
1933 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 whether such
indemnification by it is against public policy as expressed in the Securities
Act of 1933 and will be governed by the final adjudication of such issue.

           The undersigned registrant hereby undertakes that:

                  (1) For purposes of determining any liability under the
           Securities Act of 1933, the information omitted from the form of
           prospectus filed as part of this registration statement in reliance
           upon Rule 430A and contained in a form of prospectus filed by the
           registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the
           Securities Act of 1933 shall be deemed to be part of this
           registration statement as of the time it was declared effective.

                  (2) For the purposes of determining any liability under the
           Securities Act of 1933, each post-effective amendment that contains a
           form of prospectus 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-3





           The undersigned registrant hereby undertakes to provide to the
Underwriters at the closing specified in the U.S. Underwriting Agreement and the
International Underwriting Agreement certificates in such denominations and
registered in such names as required by the Underwriters to permit prompt
delivery to each purchaser.

                                      II-4





                                   SIGNATURES

           Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has duly caused this Amendment to the Registration
Statement on Form S-1 to be signed on its behalf by the undersigned, thereunto
duly authorized, in the Borough of Elmwood Park in the State of New Jersey on
April 23, 1999.

                                           CAREINSITE, INC.


                                           By: /s/ Paul C. Suthern
                                               -------------------------------
                                               Name: Paul C. Suthern
                                               Title: President and
                                                      Chief Executive Officer


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

Signature                                  Title                     Date
- ---------                                  -----                     ----

 /s/ Paul C. Suthern              Director and Principal         April 23, 1999
- ------------------------------    Executive Officer
Paul C. Suthern 

 /s/ Paul M. Bernard              Principal Financial and        April 23, 1999
- ------------------------------    Accounting Officer
Paul M. Bernard

               *                  Director                       April 23, 1999
- ------------------------------
Roger C. Holstein

               *                  Director                       April 23, 1999
- ------------------------------
James R. Love

               *                  Director                       April 23, 1999
- ------------------------------
David M. Margulies

               *                  Director                       April 23, 1999
- ------------------------------
Charles A. Mele

               *                  Director                       April 23, 1999
- ------------------------------
Martin J. Wygod

*/s/David C. Amburgey                                            April 23, 1999
- ------------------------------
  As Attorney-in-fact






                                      II-5