SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                  SCHEDULE TO/A

       TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR SECTION 13(E)(1)
                    OF THE SECURITIES EXCHANGE ACT OF 1934

                               (Amendment No.4)

                                 SEMPRA ENERGY
        (Name Of Subject Company (issuer) and Filing Person (offeror))


                        COMMON STOCK, WITHOUT PAR VALUE
                        (Title of Class of Securities)

                                   816851109
                     (CUSIP Number of Class of Securities)


                              JOHN R. LIGHT, ESQ.
                 EXECUTIVE VICE PRESIDENT AND GENERAL COUNSEL
                                 SEMPRA ENERGY
                                101 ASH STREET
                          SAN DIEGO, CALIFORNIA 92101-3017
                                (619) 696-2034
(Name, Address and Telephone Number of Person Authorized to Receive Notices and
               Communications on Behalf of the Filing Person(s))

                                   COPY TO:
                            BARRY M. CLARKSON, ESQ.
                               LATHAM & WATKINS
                           701 B STREET, SUITE 2100
                       SAN DIEGO, CALIFORNIA 92101-8197
                                (619) 236-1234

Check the appropriate boxes below to designate any transactions to which the
statement relates:

[ ]     third-party tender offer subject to Rule 14d-1
[X]     issuer tender offer subject to Rule 13e-4
[ ]     going private transaction subject to Rule 13e-3
[ ]     amendment to Schedule 13D under Rule 13d-2

Check the following box if the filing is a final amendment reporting the results
of the tender offer [ ]


         This Amendment No. 4 to Tender Offer Statement on Schedule TO relates
to the offer by Sempra Energy, a California corporation, to purchase shares of
its common stock, without par value. Sempra is offering to purchase up to
36,000,000 shares at a price not in excess of $20.00 nor less than $17.50 per
share, net to the seller in cash, without interest, as specified by shareholders
tendering their shares. Sempra's offer is being made upon the terms and subject
to the conditions set forth in the Offer to Purchase dated January 26, 2000 and
in the related Letter of Transmittal, which, as amended or supplemented from
time to time, together constitute the offer. All shares tendered and purchased
will include the associated preferred stock purchase rights issued pursuant to a
Rights Agreement dated as of May 26, 1998 between Sempra and First Chicago Trust
Company of New York, as rights agent, and, unless the context otherwise
requires, all references to shares include the associated preferred stock
purchase rights.

     The Offer to Purchase and the related Letter of Transmittal, copies of
which were previously filed with this Schedule TO as Exhibits (a)(1)(i) and
(a)(1)(ii), are hereby amended as follows in response to Item 1 of this Tender
Offer Statement on Schedule TO:

     "The information under the heading "Until what time can I withdraw
previously tendered shares? (Page 13)" of the Summary Term Sheet of the Offer to
Purchase is deleted and the following is inserted in lieu thereof:

     You may withdraw your tendered shares at any time before 5:00 p.m., New
York City time, on Friday, February 25, 2000. If the offer is extended by Sempra
beyond that time, you may withdraw your tendered shares at any time until the
expiration of the offer. In addition, unless Sempra accepts your tendered shares
for payment before 12:00 Midnight, New York City time, on Wednesday, March 22,
2000, you may withdraw your tendered shares at any time after March 22, 2000."

     The Offer to Purchase and the related Letter of Transmittal, copies of
which were previously filed with this Schedule TO as Exhibits (a)(1)(i) and
(a)(1)(ii), are hereby amended as follows in response to Items 1 and 4 of this
Tender Offer Statement on Schedule TO:

     Each occurrence of the phrase "sole judgment" under the heading "What are
the most significant conditions to the offer? (Page 15)" of the Summary Term
Sheet and in "Section 7. Conditions of the Offer" of the Offer to Purchase is
deleted and the phrase "reasonable judgment" is inserted in lieu thereof.

     Item 12 of this Tender Offer statement on Schedule TO is hereby amended as
follows:

     The final paragraph in Exhibit (a)(5)(iv) and the paragraph under the
heading "Safe Harbor Statement" in Exhibits (a)(5)(v) and (a)(5)(vi) are deleted
and the following is inserted in lieu thereof:

     This document contains statements that are not historical facts and
constitute projections, forecasts or forward-looking statements. When we use
words like "believes," "expects," "anticipates," "intends," "plans,"
"estimates," "may," "should" or similar expressions, or when we discuss our
strategy or plans, we are making projections, forecasts or forward-looking
statements. These statements are not guarantees of performance. They involve
risks, uncertainties and assumptions that could cause our future results and
shareholder value to differ materially from those expressed in these statements.
Many of the factors that will determine these results and value are beyond our
ability to control or predict. These statements are necessarily based upon
various assumptions involving judgments with respect to the future. These risks
and uncertainties include, among others:

     .    national, international, regional and local economic, competitive and
          regulatory conditions and developments;

     .    capital market conditions, inflation rates and interest rates;

     .    energy markets, including the timing and extent of changes in
          commodity prices;

     .    business, regulatory and legal decisions;

     .    the pace of deregulation of retail natural gas and electricity
          delivery;

     .    technological developments;

     .    the timing and success of business development efforts; and

     .    other uncertainties, all of which are difficult to predict and many of
          which are beyond our control.

     These risks and uncertainties are further discussed in more detail in
Sempra's Annual Report on Form 10-K for the fiscal year ended December 31, 1998
which has been filed with the Securities and Exchange Commission and is
available through the EDGAR system without charge via its website at
www.sec.gov. Please be advised that the safe harbor protections of the Private
Securities Litigation Reform Act of 1995 are not available to statements made in
connection with a tender offer.

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                                   SIGNATURE


         After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.



Dated:    February 22, 2000                     SEMPRA ENERGY


                                        By:    /s/ CHARLES A. MCMONAGLE
                                           -------------------------------------
                                           Name:   Charles A. McMonagle
                                           Title:  Vice President and Treasurer

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