Exhibit 5.1

             [Letterhead of Cahill Gordon & Reindel]



                               February [ ], 2000

                                                                  (212) 701-3000

Gentiva Health Services, Inc.
175 Broad Hollow Road
Melville, New York  11747

                  Re:  GENTIVA HEALTH SERVICES, INC.

Ladies and Gentlemen:

                  We have acted as counsel to Gentiva Health Services, Inc., a
Delaware corporation (the "Company") in connection with its Registration
Statement on Form S-4 (No. 333-88663), as amended (the "Registration Statement")
filed by the Company with the Securities and Exchange Commission (the
"Commission") registering under the Securities Act of 1933, as amended (the
"Act") 22,122,152 shares of the Company's common stock, par value $.10 per share
(the "Common Stock"). The Common Stock is to be issued to holders of the common
stock and class B common stock of Olsten Corporation, a Delaware corporation
("Olsten") upon the consummation of the merger of Olsten and Staffing
Acquisition Corporation, a Delaware corporation ("Staffing"), pursuant to an
Agreement and Plan of Merger, dated August 17, 1999, by and among Olsten,
Staffing and Adecco SA, a societe anonyme organized under the laws of
Switzerland, as amended (the "Merger Agreement").

                  We have examined copies of such corporate records and made
such inquiries as we have deemed necessary for purposes of rendering the opinion
set forth below.



                                       -2-


                  Based upon the foregoing, in our opinion, the shares of Common
Stock to be issued by the Company, when issued in the manner and for the
consideration contemplated by the Registration Statement will be duly and
validly issued, fully paid and non-assessable.

                  In rendering the opinion set forth above, we express no
opinion as to the laws of any jurisdiction other than the General Corporation
law of the State of Delaware, including the applicable provisions of the
Delaware Constitution and the reported judicial decisions interpreting the laws,
and the federal laws of the United States of America.

                  We hereby consent to the use of our name under the caption
"Legal Matters" and to the filing of this opinion as an exhibit to the
Registration Statement. In giving such consent, we do not thereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act.

                                                     Very truly yours,
                                                     /s/ Cahill Gordon & Reindel