<PAGE>

    As filed with the Securities and Exchange Commission on October 24, 2001

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   ----------

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

                                   ----------

                         PACIFICARE HEALTH SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

               Delaware                                    95-4591529
     (State or other jurisdiction                       (I.R.S. Employer
   of incorporation or organization)                   Identification No.)

                                   ----------

               3120 Lake Center Drive, Santa Ana, California 92704
                    (Address of principal executive offices)

                                   ----------

                               2000 Employee Plan
                        2001 Employee Stock Purchase Plan
                            (Full title of the plans)

                                   ----------

                           Joseph S. Konowiecki, Esq.
                          General Counsel and Secretary
                         PacifiCare Health Systems, Inc.
                             3120 Lake Center Drive
                           Santa Ana, California 92704
                                 (714) 825-5200
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                   ----------

                                   Copies to:

                             Frederick T. Muto, Esq.
                             Barbara L. Borden, Esq.
                               Cooley Godward LLP
                               4401 Eastgate Mall
                            San Diego, CA 92121-9109
                                 (858) 550-6000

                                   ----------


<PAGE>

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
================================================================================================================================
                                                           Proposed Maximum           Proposed Maximum
    Title of Securities                                         Offering                  Aggregate                Amount of
     to be Registered        Amount to be Registered      Price per Share(1)          Offering Price(1)         Registration Fee
--------------------------------------------------------------------------------------------------------------------------------
<S>                          <C>                          <C>                        <C>                        <C>
  Common stock, par value
  $0.01 per share(2)(3)          1,500,000 shares              $14.66                   $21,990,000                 $5,498
--------------------------------------------------------------------------------------------------------------------------------
  Common stock, par value
  $0.01 per share(3)(4)          1,100,000 shares              $14.66                   $16,126,000                 $4,032
================================================================================================================================
</TABLE>

(1)  Estimated solely for the purpose of calculating the amount of the
     registration fee pursuant to Rule 457(h), on the basis of the average of
     the high and low prices of the Registrant's common stock as reported on the
     Nasdaq National Market on a date within five business days of the filing
     hereof with respect to the shares being registered.

(2)  Underlying shares of common stock issued under the Registrant's 2000
     Employee Plan.

(3)  Pursuant to Rule 416(a) under the Securities Act of 1933, this Registration
     Statement shall also cover any additional shares of the Registrant's common
     stock that become issuable under the plan by reason of any stock dividend,
     stock split, recapitalization or other similar transaction effected without
     receipt of consideration that increases the number of outstanding shares of
     the Registrant's common stock.

(4)  Underlying shares of common stock issued under the Registrant's 2001
     Employee Stock Purchase Plan.

================================================================================

                                       2.
<PAGE>

                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents filed by PacifiCare Health Systems, Inc., a
Delaware corporation (the "Registrant"), with the Securities and Exchange
Commission are incorporated by reference into this Registration Statement:

     (a) The Registrant's Annual Report on Form 10-K for the fiscal year ended
December 31, 2000 (the "Form 10-K"), which is the Registrant's latest Annual
Report on Form 10-K filed pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 (the "Exchange Act") and which contains audited financial
statements for the Registrant's latest fiscal year for which a Form 10-K was
required to have been filed.

     (b) The Registrant's Quarterly Reports on Form 10-Q for the quarters ended
March 31, 2001 and June 30, 2001.

     (c) The Registrant's Current Reports on Form 8-K filed on January 25, 2001,
June 1, 2001, June 18, 2001, June 19, 2001, June 22, 2001, June 26, 2001, July
9, 2001, July 12, 2001, July 25, 2001, August 1, 2001, August 28, 2001,
September 4, 2001 and October 4, 2001.

     (d) The Registrant's Form S-8 filed on August 13, 2001 (file number
333-67388) relating to the Registrant's 2000 Employee Plan.

     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 securities offered 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 of this Registration
Statement from the date of the filing of such documents.


                            DESCRIPTION OF SECURITIES

     The Registrant's certificate of incorporation authorizes the Registrant to
issue 200,000,000 shares of common stock, par value $0.01 per share, and
40,000,000 shares of preferred stock, par value $0.01 per share. As of October
10, 2001, approximately 34,530,000 shares of common stock were outstanding and
no shares of preferred stock were outstanding.


COMMON STOCK

     VOTING. Common stockholders are entitled to one (1) vote per share for the
election of directors and on all other matters that require stockholder
approval.

     DIVIDENDS AND OTHER DISTRIBUTIONS. Holders of the Registrant's common stock
are entitled to share in an equal amount per share in any dividends declared by
the Registrant's board of directors and paid out of legally available assets.

     DISTRIBUTION ON DISSOLUTION, ETC. In the event of the Registrant's
liquidation, dissolution or winding up, holders of the Registrant's common stock
are entitled to share ratably in the assets remaining after payment of
liabilities and the liquidation preferences of any outstanding preferred stock.

     PREEMPTIVE RIGHTS. The Registrant's common stock does not carry any
preemptive rights enabling a holder to subscribe for, or receive shares of, any
class of the Registrant's common stock or any other securities convertible into
shares of any class of the Registrant's common stock.


                                       3.
<PAGE>

STOCKHOLDER RIGHTS AGREEMENT


In November 1999, the Registrant's board of directors adopted a stockholder
rights agreement to protect stockholder rights in the event of a proposed
takeover. The board of directors declared a dividend of one right for each share
of the Registrant's common stock outstanding as of November 19, 1999. The right
entitles the registered holder to purchase from the Registrant 1/100th of a
share of Series A junior participating preferred stock at a price of $180 per
1/100th of a preferred share. Similar rights will generally be issued in respect
of common stock issued after November 19, 1999.


                     INTERESTS OF NAMED EXPERTS AND COUNSEL

Not applicable.


                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

Under Section 145 of the Delaware General Corporation Law, the Registrant has
broad powers to indemnify its directors and officers against liabilities they
may incur in such capacities, including liabilities under the Securities Act of
1933, as amended (the "Securities Act"). The Registrant's bylaws provide that
the Registrant will indemnify its directors, officers, employees or agents in a
manner consistent with the provisions of the Delaware General Corporation Law.

In addition, the Registrant's certificate of incorporation provides that,
pursuant to Delaware law, its directors shall not be liable for monetary damages
for breach of the directors' fiduciary duty of care to the Registrant and its
stockholders. This provision in the certificate of incorporation does not
eliminate the duty of care, and in appropriate circumstances equitable remedies
such as injunctive or other forms of non-monetary relief will remain available
under Delaware law. In addition, each director will continue to be subject to
liability for breach of the director's duty of loyalty to the Registrant, for
acts or omissions not in good faith or involving intentional misconduct or a
knowing violation of law, for actions leading to improper personal benefit to
the director, and for payment of dividends or approval of stock repurchases or
redemptions that are unlawful under Delaware law. The provision also does not
affect a director's responsibilities under any other law, such as the federal
securities laws or state or federal environmental laws.

The Registrant maintains a policy providing directors' and officers' liability
insurance, which insures directors and officers of the Registrant in certain
circumstances.

Insofar as the indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers or persons controlling the Registrant
pursuant to the foregoing provisions, the Registrant has been informed 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.

                       EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.


                                       4.
<PAGE>

                                    EXHIBITS

The following exhibits are filed as part of this Registration Statement:


     4.1    2000 Employee Plan (incorporated by reference to Exhibit 4.1 to the
            Registrant's Form S-8 filed on August 17, 2000)

     4.2    2001 Employee Stock Purchase Plan

     4.3    The Registrant's Amended and Restated Certificate of Incorporation
            (incorporated by reference to Exhibit 99.1 to the Registrant's
            Registration Statement on Form S-3 filed on July 16, 1999)

     4.4    Form of Specimen Certificate for the Registrant's common stock
            (incorporated by reference to Exhibit 4.02 to the Registrant's Form
            10-K for the year ended December 31, 1999)

     4.5    Rights Agreement, dated as of November 19, 1999, between the
            Registrant and ChaseMellon Shareholder Services, L.L.C.
            (incorporated by reference to Exhibit 99.2 to the Registrant's Form
            8-K filed on November 19, 1999)

     5.1    Opinion of Cooley Godward LLP

    15.1    Acknowledgement of Ernst & Young LLP

    23.1    Consent of Ernst & Young LLP

    23.2    Consent of Cooley Godward LLP (included in Exhibit 5.1)

    24.1    Power of Attorney (appears on signature page)


                                  UNDERTAKINGS

1.   The undersigned 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 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.

     (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 undersigned Registrant hereby undertakes that, for 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 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


                                       5.
<PAGE>

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 and will be governed by the final adjudication
of such issue.


                                       6.
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, 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 City of Santa Ana, State of California, on this 24th day of
October, 2001.


                                                 PACIFICARE HEALTH SYSTEMS, INC.


                                                 By: /s/ Howard G. Phanstiel
                                                     ---------------------------
                                                         Howard G. Phanstiel
                                                 Title:  President and Chief
                                                         Executive Officer


                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Howard G. Phanstiel and Gregory W. Scott,
and each or any one of them, his or her true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him or her and on
his or her behalf, and in his or her name, place and stead, in any and all
capacities, to sign any and all amendments (including post-effective amendments)
to this Registration Statement, and to file the same, with all exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite or necessary to be done in connection therewith, as fully to all
intents and purposes as he or she might or could do in person, hereby ratifying
and confirming all that said attorneys-in-fact and agents, or any of them, or
their or his substitutes or substitute, may lawfully do or cause to be done by
virtue hereof and the Registrant hereby confers like authority on its behalf.


                                       7.
<PAGE>

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


<TABLE>
<CAPTION>
              SIGNATURE                      TITLE                       DATE
              ---------                      -----                       ----
<S>                              <C>                               <C>

/s/ Howard G. Phanstiel          President and Chief Executive     October 24, 2001
-------------------------------  Officer (Principal Executive
    HOWARD G. PHANSTIEL          Officer)

/s/ Gregory W. Scott             Executive Vice President and      October 24, 2001
-------------------------------  Chief Financial Officer
    GREGORY W. SCOTT             (Principal Financial Officer)

/s/ Susan L. Berkel              Senior Vice President, Finance    October 24, 2001
-------------------------------  and Corporate Controller
    SUSAN L. BERKEL              (Chief Accounting Officer)

/s/ David A. Reed                Chairman of the Board             October 24, 2001
-------------------------------
    DAVID A. REED

/s/ Bradley C. Call              Director                          October 24, 2001
-------------------------------
    BRADLEY C. CALL

    Shirley S. Chater            Director                          October 24, 2001
-------------------------------
    SHIRLEY S. CHATER

/s/ Terry O. Hartshorn           Director                          October 24, 2001
-------------------------------
    TERRY O. HARTSHORN

/s/ Arthur B. Laffer, Ph.D.      Director                          October 24, 2001
-------------------------------
    ARTHUR B. LAFFER, PH.D.

/s/ Gary L. Leary                Director                          October 24, 2001
-------------------------------
    GARY L. LEARY

/s/ Sanford M. Litvack           Director                          October 24, 2001
-------------------------------
    SANFORD M. LITVACK

/s/ Warren E. Pinckert, II       Director                          October 24, 2001
-------------------------------
    WARREN E. PINCKERT, II

/s/ Lloyd E. Ross                Director                          October 24, 2001
-------------------------------
    LLOYD E. ROSS
</TABLE>


                                       8.
<PAGE>

                                  EXHIBIT INDEX


   EXHIBIT
   NUMBER                          DESCRIPTION
   ------                          -----------

     4.1    2000 Employee Plan (incorporated by reference to Exhibit 4.1 to the
            Registrant's Form S-8 filed on August 17, 2000)

     4.2    2001 Employee Stock Purchase Plan

     4.3    The Registrant's Amended and Restated Certificate of Incorporation
            (incorporated by reference to Exhibit 99.1 to the Registrant's
            Registration Statement on Form S-3 filed on July 16, 1999)

     4.4    Form of Specimen Certificate for the Registrant's common stock
            (incorporated by reference to Exhibit 4.02 to the Registrant's Form
            10-K for the year ended December 31, 1999)

     4.5    Rights Agreement, dated as of November 19, 1999, between the
            Registrant and ChaseMellon Shareholder Services, L.L.C.
            (incorporated by reference to Exhibit 99.2 to the Registrant's Form
            8-K filed on November 19, 1999)

     5.1    Opinion of Cooley Godward LLP

    15.1    Acknowledgement of Ernst & Young LLP

    23.1    Consent of Ernst & Young LLP

    23.2    Consent of Cooley Godward LLP (included in Exhibit 5.1)

    24.1    Power of Attorney (appears on signature page)
[{"type": "S-8", "sequence": "1", "filename": "a76337ors-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 20810}]
{"company-data": {"conformed-name": "PACIFICARE HEALTH SYSTEMS INC /DE/", "cik": "0001027974", "assigned-sic": "6324", "irs-number": "954591529", "state-of-incorporation": "DE", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-72168", "film-number": "1765221"}, "business-address": {"street1": "3120 LAKE CENTER DRIVE", "city": "SANTA ANA", "state": "CA", "zip": "92704", "phone": "7148255200"}, "mail-address": {"street1": "3120 LAKE CENTER DRIVE", "city": "SANTA ANA", "state": "CA", "zip": "92704"}, "former-company": {"former-conformed-name": "N T HOLDINGS INC", "date-changed": "19961204"}}
As filed with the Securities and Exchange Commission on October 24, 2001

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   ----------

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

                                   ----------

                         PACIFICARE HEALTH SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)

               Delaware                                    95-4591529
     (State or other jurisdiction                       (I.R.S. Employer
   of incorporation or organization)                   Identification No.)

                                   ----------

               3120 Lake Center Drive, Santa Ana, California 92704
                    (Address of principal executive offices)

                                   ----------

                               2000 Employee Plan
                        2001 Employee Stock Purchase Plan
                            (Full title of the plans)

                                   ----------

                           Joseph S. Konowiecki, Esq.
                          General Counsel and Secretary
                         PacifiCare Health Systems, Inc.
                             3120 Lake Center Drive
                           Santa Ana, California 92704
                                 (714) 825-5200
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                   ----------

                                   Copies to:

                             Frederick T. Muto, Esq.
                             Barbara L. Borden, Esq.
                               Cooley Godward LLP
                               4401 Eastgate Mall
                            San Diego, CA 92121-9109
                                 (858) 550-6000

                                   ----------
CALCULATION OF REGISTRATION FEE
================================================================================================================================
                                                           Proposed Maximum           Proposed Maximum
    Title of Securities                                         Offering                  Aggregate                Amount of
     to be Registered        Amount to be Registered      Price per Share(1)          Offering Price(1)         Registration Fee
--------------------------------------------------------------------------------------------------------------------------------
Common stock, par value
  $0.01 per share(2)(3)          1,500,000 shares              $14.66                   $21,990,000                 $5,498
--------------------------------------------------------------------------------------------------------------------------------
  Common stock, par value
  $0.01 per share(3)(4)          1,100,000 shares              $14.66                   $16,126,000                 $4,032
================================================================================================================================
(1)  Estimated solely for the purpose of calculating the amount of the
     registration fee pursuant to Rule 457(h), on the basis of the average of
     the high and low prices of the Registrant's common stock as reported on the
     Nasdaq National Market on a date within five business days of the filing
     hereof with respect to the shares being registered.

(2)  Underlying shares of common stock issued under the Registrant's 2000
     Employee Plan.

(3)  Pursuant to Rule 416(a) under the Securities Act of 1933, this Registration
     Statement shall also cover any additional shares of the Registrant's common
     stock that become issuable under the plan by reason of any stock dividend,
     stock split, recapitalization or other similar transaction effected without
     receipt of consideration that increases the number of outstanding shares of
     the Registrant's common stock.

(4)  Underlying shares of common stock issued under the Registrant's 2001
     Employee Stock Purchase Plan.

================================================================================

                                       2.
INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents filed by PacifiCare Health Systems, Inc., a
Delaware corporation (the "Registrant"), with the Securities and Exchange
Commission are incorporated by reference into this Registration Statement:

     (a) The Registrant's Annual Report on Form 10-K for the fiscal year ended
December 31, 2000 (the "Form 10-K"), which is the Registrant's latest Annual
Report on Form 10-K filed pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 (the "Exchange Act") and which contains audited financial
statements for the Registrant's latest fiscal year for which a Form 10-K was
required to have been filed.

     (b) The Registrant's Quarterly Reports on Form 10-Q for the quarters ended
March 31, 2001 and June 30, 2001.

     (c) The Registrant's Current Reports on Form 8-K filed on January 25, 2001,
June 1, 2001, June 18, 2001, June 19, 2001, June 22, 2001, June 26, 2001, July
9, 2001, July 12, 2001, July 25, 2001, August 1, 2001, August 28, 2001,
September 4, 2001 and October 4, 2001.

     (d) The Registrant's Form S-8 filed on August 13, 2001 (file number
333-67388) relating to the Registrant's 2000 Employee Plan.

     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 securities offered 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 of this Registration
Statement from the date of the filing of such documents.

                            DESCRIPTION OF SECURITIES

     The Registrant's certificate of incorporation authorizes the Registrant to
issue 200,000,000 shares of common stock, par value $0.01 per share, and
40,000,000 shares of preferred stock, par value $0.01 per share. As of October
10, 2001, approximately 34,530,000 shares of common stock were outstanding and
no shares of preferred stock were outstanding.

COMMON STOCK

     VOTING. Common stockholders are entitled to one (1) vote per share for the
election of directors and on all other matters that require stockholder
approval.

     DIVIDENDS AND OTHER DISTRIBUTIONS. Holders of the Registrant's common stock
are entitled to share in an equal amount per share in any dividends declared by
the Registrant's board of directors and paid out of legally available assets.

     DISTRIBUTION ON DISSOLUTION, ETC. In the event of the Registrant's
liquidation, dissolution or winding up, holders of the Registrant's common stock
are entitled to share ratably in the assets remaining after payment of
liabilities and the liquidation preferences of any outstanding preferred stock.

     PREEMPTIVE RIGHTS. The Registrant's common stock does not carry any
preemptive rights enabling a holder to subscribe for, or receive shares of, any
class of the Registrant's common stock or any other securities convertible into
shares of any class of the Registrant's common stock.

                                       3.
STOCKHOLDER RIGHTS AGREEMENT

In November 1999, the Registrant's board of directors adopted a stockholder
rights agreement to protect stockholder rights in the event of a proposed
takeover. The board of directors declared a dividend of one right for each share
of the Registrant's common stock outstanding as of November 19, 1999. The right
entitles the registered holder to purchase from the Registrant 1/100th of a
share of Series A junior participating preferred stock at a price of $180 per
1/100th of a preferred share. Similar rights will generally be issued in respect
of common stock issued after November 19, 1999.

                     INTERESTS OF NAMED EXPERTS AND COUNSEL

Not applicable.

                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

Under Section 145 of the Delaware General Corporation Law, the Registrant has
broad powers to indemnify its directors and officers against liabilities they
may incur in such capacities, including liabilities under the Securities Act of
1933, as amended (the "Securities Act"). The Registrant's bylaws provide that
the Registrant will indemnify its directors, officers, employees or agents in a
manner consistent with the provisions of the Delaware General Corporation Law.

In addition, the Registrant's certificate of incorporation provides that,
pursuant to Delaware law, its directors shall not be liable for monetary damages
for breach of the directors' fiduciary duty of care to the Registrant and its
stockholders. This provision in the certificate of incorporation does not
eliminate the duty of care, and in appropriate circumstances equitable remedies
such as injunctive or other forms of non-monetary relief will remain available
under Delaware law. In addition, each director will continue to be subject to
liability for breach of the director's duty of loyalty to the Registrant, for
acts or omissions not in good faith or involving intentional misconduct or a
knowing violation of law, for actions leading to improper personal benefit to
the director, and for payment of dividends or approval of stock repurchases or
redemptions that are unlawful under Delaware law. The provision also does not
affect a director's responsibilities under any other law, such as the federal
securities laws or state or federal environmental laws.

The Registrant maintains a policy providing directors' and officers' liability
insurance, which insures directors and officers of the Registrant in certain
circumstances.

Insofar as the indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers or persons controlling the Registrant
pursuant to the foregoing provisions, the Registrant has been informed 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.

                       EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.

                                       4.
EXHIBITS

The following exhibits are filed as part of this Registration Statement:

     4.1    2000 Employee Plan (incorporated by reference to Exhibit 4.1 to the
            Registrant's Form S-8 filed on August 17, 2000)

     4.2    2001 Employee Stock Purchase Plan

     4.3    The Registrant's Amended and Restated Certificate of Incorporation
            (incorporated by reference to Exhibit 99.1 to the Registrant's
            Registration Statement on Form S-3 filed on July 16, 1999)

     4.4    Form of Specimen Certificate for the Registrant's common stock
            (incorporated by reference to Exhibit 4.02 to the Registrant's Form
            10-K for the year ended December 31, 1999)

     4.5    Rights Agreement, dated as of November 19, 1999, between the
            Registrant and ChaseMellon Shareholder Services, L.L.C.
            (incorporated by reference to Exhibit 99.2 to the Registrant's Form
            8-K filed on November 19, 1999)

     5.1    Opinion of Cooley Godward LLP

    15.1    Acknowledgement of Ernst & Young LLP

    23.1    Consent of Ernst & Young LLP

    23.2    Consent of Cooley Godward LLP (included in Exhibit 5.1)

    24.1    Power of Attorney (appears on signature page)

                                  UNDERTAKINGS

1.   The undersigned 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 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.

     (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 undersigned Registrant hereby undertakes that, for 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 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

                                       5.
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 and will be governed by the final adjudication
of such issue.

                                       6.
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, 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 City of Santa Ana, State of California, on this 24th day of
October, 2001.

                                                 PACIFICARE HEALTH SYSTEMS, INC.

                                                 By: /s/ Howard G. Phanstiel
                                                     ---------------------------
                                                         Howard G. Phanstiel
                                                 Title:  President and Chief
                                                         Executive Officer

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Howard G. Phanstiel and Gregory W. Scott,
and each or any one of them, his or her true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him or her and on
his or her behalf, and in his or her name, place and stead, in any and all
capacities, to sign any and all amendments (including post-effective amendments)
to this Registration Statement, and to file the same, with all exhibits thereto,
and other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite or necessary to be done in connection therewith, as fully to all
intents and purposes as he or she might or could do in person, hereby ratifying
and confirming all that said attorneys-in-fact and agents, or any of them, or
their or his substitutes or substitute, may lawfully do or cause to be done by
virtue hereof and the Registrant hereby confers like authority on its behalf.

                                       7.
Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
SIGNATURE                      TITLE                       DATE
              ---------                      -----                       ----
/s/ Howard G. Phanstiel          President and Chief Executive     October 24, 2001
-------------------------------  Officer (Principal Executive
    HOWARD G. PHANSTIEL          Officer)

/s/ Gregory W. Scott             Executive Vice President and      October 24, 2001
-------------------------------  Chief Financial Officer
    GREGORY W. SCOTT             (Principal Financial Officer)

/s/ Susan L. Berkel              Senior Vice President, Finance    October 24, 2001
-------------------------------  and Corporate Controller
    SUSAN L. BERKEL              (Chief Accounting Officer)

/s/ David A. Reed                Chairman of the Board             October 24, 2001
-------------------------------
    DAVID A. REED

/s/ Bradley C. Call              Director                          October 24, 2001
-------------------------------
    BRADLEY C. CALL

    Shirley S. Chater            Director                          October 24, 2001
-------------------------------
    SHIRLEY S. CHATER

/s/ Terry O. Hartshorn           Director                          October 24, 2001
-------------------------------
    TERRY O. HARTSHORN

/s/ Arthur B. Laffer, Ph.D.      Director                          October 24, 2001
-------------------------------
    ARTHUR B. LAFFER, PH.D.

/s/ Gary L. Leary                Director                          October 24, 2001
-------------------------------
    GARY L. LEARY

/s/ Sanford M. Litvack           Director                          October 24, 2001
-------------------------------
    SANFORD M. LITVACK

/s/ Warren E. Pinckert, II       Director                          October 24, 2001
-------------------------------
    WARREN E. PINCKERT, II

/s/ Lloyd E. Ross                Director                          October 24, 2001
-------------------------------
    LLOYD E. ROSS
8.
EXHIBIT INDEX

   EXHIBIT
   NUMBER                          DESCRIPTION
   ------                          -----------

     4.1    2000 Employee Plan (incorporated by reference to Exhibit 4.1 to the
            Registrant's Form S-8 filed on August 17, 2000)

     4.2    2001 Employee Stock Purchase Plan

     4.3    The Registrant's Amended and Restated Certificate of Incorporation
            (incorporated by reference to Exhibit 99.1 to the Registrant's
            Registration Statement on Form S-3 filed on July 16, 1999)

     4.4    Form of Specimen Certificate for the Registrant's common stock
            (incorporated by reference to Exhibit 4.02 to the Registrant's Form
            10-K for the year ended December 31, 1999)

     4.5    Rights Agreement, dated as of November 19, 1999, between the
            Registrant and ChaseMellon Shareholder Services, L.L.C.
            (incorporated by reference to Exhibit 99.2 to the Registrant's Form
            8-K filed on November 19, 1999)

     5.1    Opinion of Cooley Godward LLP

    15.1    Acknowledgement of Ernst & Young LLP

    23.1    Consent of Ernst & Young LLP

    23.2    Consent of Cooley Godward LLP (included in Exhibit 5.1)

    24.1    Power of Attorney (appears on signature page)