UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-CSR


   CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES

                  Investment Company Act file number 811-4757

                        SMITH BARNEY SECTOR SERIES INC.
               (Exact name of registrant as specified in charter)

                      125 Broad Street, New York, NY 10004
               (Address of principal executive offices) (Zip code)

                            Christina T. Sydor, Esq.
                            300 First Stamford Place
                               Stamford, CT 06902
                     (Name and address of agent for service)

              Registrant's telephone number, including area code:

                                 (800) 451-2010

                      Date of fiscal year end: OCTOBER 31
                    Date of reporting period: APRIL 30, 2003



ITEM 1.   REPORT TO STOCKHOLDERS.

          The SEMI-ANNUAL Report to Stockholders is filed herewith.






                                  SMITH BARNEY
                               SECTOR SERIES INC.


                                  SMITH BARNEY
                              HEALTH SCIENCES FUND

             Research Series | Semi-annual report | April 30, 2003







                                 [LOGO OMITTED]
                           SMITH BARNEY MUTUAL FUNDS


                 YOUR SERIOUS MONEY. PROFESSIONALLY MANAGED(R)


 YOUR SERIOUS MONEY. PROFESSIONALLY MANAGED.(R) is a registered service mark of
                         Citigroup Global Markets Inc.


          NOT FDIC INSURED  o  NOT BANK GUARANTEED  o  MAY LOSE VALUE



[GRAPHIC OMITTED] Research Series

Semi-Annual Report  o  April 30, 2003

SMITH BARNEY HEALTH SCIENCES FUND

SMITH BARNEY FUND MANAGEMENT LLC

Smith Barney Fund Management LLC is the investment manager to the Fund. Citi
Fund Management Inc. is the subadviser. The Fund's management team follows a
systematic and rigorous approach designed to provide appropriate exposure to the
market sector.

FUND OBJECTIVE*

The Fund seeks long-term capital appreciation by investing primarily in common
stocks. The Fund normally invests at least 80% of its assets in securities of
companies principally engaged in the design, manufacture, or sale of products or
services used for or in connection with healthcare or medicine.

FUND FACTS

FUND INCEPTION
- ----------------------
February 28, 2000

WHAT'S INSIDE

Letter From the Chairman ....................................................  1
Schedule of Investments .....................................................  2
Statement of Assets and Liabilities .........................................  4
Statement of Operations .....................................................  5
Statements of Changes in Net Assets .........................................  6
Notes to Financial Statements ...............................................  7
Financial Highlights ........................................................ 11


- ----------
*    Since the Fund focuses its investments on companies involved in the health
     sciences, an investment in the Fund may involve a greater degree of risk
     than an investment in other mutual funds with greater diversification.


[LOGO OMITTED]
SMITH BARNEY MUTUAL FUNDS

YOUR SERIOUS MONEY. PROFESSIONALLY MANAGED(R)

YOUR SERIOUS MONEY. PROFESSIONALLY MANAGED.(R) is a registered service mark of
Citigroup Global Markets Inc.

Investment Products: Not Fdic Insured  o  Not Bank Guaranteed  o  May Lose Value



                            LETTER FROM THE CHAIRMAN


                                                         [GRAPHIC OMITTED]
                                                         R. JAY GERKEN

                                                         CHAIRMAN, PRESIDENT AND
                                                         CHIEF EXECUTIVE OFFICER


DEAR SHAREHOLDER,

The philosopher Bertrand Russell famously remarked that, "Change is one thing,
progress is another." You will notice in the following pages that we have begun
to implement some changes to your shareholder report and we will be reflecting
other changes in future reports. Our aim is to make meaningful improvements in
reporting on the management of your Fund and its performance, not just to enact
change for change's sake. Please bear with us during this transition period.

We know that you have questions about fund managers' decisions and plans, and we
want to be sure that you have easy access to the information you need. Keeping
investors informed is, and always will be, one of my top priorities as Chairman
of your Fund. To that end, we encourage you to go to our website:
www.smithbarneymutualfunds.com(1) where you can find additional insight on your
Fund.

I invite you to read this report in full. Please take the opportunity to talk to
your financial adviser about this report or any other questions or concerns you
have about your Fund and your financial future. As always, thank you for
entrusting your assets to us. We look forward to helping you continue to meet
your financial goals.

Sincerely,

/s/R. JAY GERKEN
- -------------------
R. Jay Gerken

Chairman, President and Chief Executive Officer

MAY 23, 2003


- ----------
(1)  MATTERS REFERENCED ARE NOT INCORPORATED BY REFERENCE UNLESS OTHERWISE
     STATED.


  1  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders





SCHEDULE OF INVESTMENTS (UNAUDITED)                               APRIL 30, 2003




     SHARES                                SECURITY                                VALUE
=============================================================================================
                                                                          
COMMON STOCK -- 99.6%

BIOTECHNOLOGY -- 15.0%
         74,636     Amgen Inc.*                                                 $ 4,575,933
         67,600     Enzon Pharmaceuticals, Inc.*                                    927,472
         21,000     Genentech, Inc.*                                                797,790
          8,810     Genzyme Corp.*                                                  354,867
         35,488     Gilead Sciences, Inc.*                                        1,637,416
          9,700     IDEC Pharmaceuticals Corp.*                                     317,675
- ---------------------------------------------------------------------------------------------
                                                                                  8,611,153
- ---------------------------------------------------------------------------------------------

HOSPITAL NURSING MANAGEMENT -- 3.5%
         52,200     HCA Inc.                                                      1,675,620
         24,100     Tenet Healthcare Corp.*                                         357,644
- ---------------------------------------------------------------------------------------------
                                                                                  2,033,264
- ---------------------------------------------------------------------------------------------

MAJOR PHARMACEUTICALS -- 50.0%
        104,812     Abbott Laboratories                                           4,258,511
         29,600     Biovail Corp.*                                                1,070,040
         46,998     Bristol-Myers Squibb Co.                                      1,200,329
         43,904     Eli Lilly & Co.                                               2,801,953
         99,944     Johnson & Johnson                                             5,632,844
         49,214     Merck & Co. Inc.                                              2,863,271
        186,678     Pfizer Inc.                                                   5,740,348
         25,800     Teva Pharmaceutical Industries Ltd., Sponsored ADR            1,204,860
         91,462     Wyeth                                                         3,981,341
- ---------------------------------------------------------------------------------------------
                                                                                 28,753,497
- ---------------------------------------------------------------------------------------------

MANAGED HEALTHCARE -- 3.8%
          8,300     Aetna Inc.                                                      413,340
          8,200     Anthem, Inc.*                                                   562,848
          7,854     UnitedHealth Group Inc.                                         723,589
          6,188     WellPoint Health Networks, Inc.*                                469,917
- ---------------------------------------------------------------------------------------------
                                                                                  2,169,694
- ---------------------------------------------------------------------------------------------

MEDICAL/DENTAL DISTRIBUTORS -- 2.5%
         15,496     Cardinal Health, Inc.                                           856,619
         20,454     McKesson, Inc.                                                  567,394
- ---------------------------------------------------------------------------------------------
                                                                                  1,424,013
- ---------------------------------------------------------------------------------------------

MEDICAL ELECTRONICS -- 12.8%

         26,100     Boston Scientific Corp.*                                      1,123,605
         11,400     Guidant Corp.*                                                  444,486
         85,054     Medtronic, Inc.                                               4,060,478
         32,700     St. Jude Medical, Inc.                                        1,715,442
- ---------------------------------------------------------------------------------------------
                                                                                  7,344,011
- ---------------------------------------------------------------------------------------------

MEDICAL SPECIALTIES -- 5.1%
         21,634     Baxter International Inc.                                       497,582
         14,027     Becton, Dickinson & Co.                                         496,556
          5,849     C.R. Bard, Inc.                                                 370,710
         34,000     Zimmer Holdings, Inc.*                                        1,594,600
- ---------------------------------------------------------------------------------------------
                                                                                  2,959,448
- ---------------------------------------------------------------------------------------------



                       SEE NOTES TO FINANCIAL STATEMENTS.

  2  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders




SCHEDULE OF INVESTMENTS (UNAUDITED) (CONTINUED)                   APRIL 30, 2003



     SHARES                                SECURITY                                VALUE
=============================================================================================
                                                                             
OTHER PHARMACEUTICALS -- 4.9%
          6,239     Allergan, Inc.                                              $   438,290
          5,400     AmerisourceBergen Corp.                                         312,390
         39,700     Forest Laboratories, Inc.*                                    2,053,284
- ---------------------------------------------------------------------------------------------
                                                                                  2,803,964
- ---------------------------------------------------------------------------------------------

SERVICES TO THE HEALTH INDUSTRY -- 2.0%
         18,700     Alcon, Inc.*                                                    823,735
         20,153     IMS Health, Inc.                                                310,356
- ---------------------------------------------------------------------------------------------
                                                                                  1,134,091
- ---------------------------------------------------------------------------------------------
                    TOTAL COMMON STOCK
                    (Cost-- $57,949,283)                                         57,233,135
=============================================================================================
      FACE
     AMOUNT                                SECURITY                                VALUE
=============================================================================================

REPURCHASE AGREEMENT -- 0.4%
       $224,000     UBS PaineWebber Inc., 1.330% due 5/1/03; Proceeds at
                      maturity -- $224,008; (Fully collateralized by Fannie Mae
                      Bonds, 3.550% due 6/11/04; Market value-- $233,738)
                      (Cost-- $224,000)                                             224,000
=============================================================================================
                    TOTAL INVESTMENTS -- 100%
                    (Cost-- $58,173,283**)                                      $57,457,135
=============================================================================================


  * NON-INCOME PRODUCING SECURITY.

 ** AGGREGATE COST FOR FEDERAL INCOME TAX PURPOSES IS SUBSTANTIALLY THE SAME.

    Abbreviation used in this schedule:
    -----------------------------------
    ADR -- American Depositary Receipt


                       SEE NOTES TO FINANCIAL STATEMENTS.

  3  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders






STATEMENT OF ASSETS AND LIABILITIES (UNAUDITED)                              APRIL 30, 2003

                                                                             
ASSETS:
     Investments, at value (Cost-- $58,173,283)                                 $57,457,135
     Cash                                                                               412
     Receivable for securities sold                                               1,425,409
     Receivable for Fund shares sold                                                 53,039
     Dividends and interest receivable                                               41,161
- ---------------------------------------------------------------------------------------------
     TOTAL ASSETS                                                                58,977,156
- ---------------------------------------------------------------------------------------------

LIABILITIES:
     Payable for Fund shares purchased                                               67,131
     Distribution fees payable                                                       37,555
     Management fee payable                                                          29,580
     Accrued expenses                                                               139,717
- ---------------------------------------------------------------------------------------------
     TOTAL LIABILITIES                                                              273,983
- ---------------------------------------------------------------------------------------------
TOTAL NET ASSETS                                                                $58,703,173
=============================================================================================

NET ASSETS:
     Par value of capital shares                                                $     5,860
     Capital paid in excess of par value                                         73,239,149
     Accumulated net investment loss                                               (252,218)
     Accumulated net realized loss from security transactions                   (13,573,470)
     Net unrealized depreciation of investments                                    (716,148)
- ---------------------------------------------------------------------------------------------
TOTAL NET ASSETS                                                                $58,703,173
=============================================================================================

SHARES OUTSTANDING:
     Class A                                                                      1,584,340
     ----------------------------------------------------------------------------------------
     Class B                                                                      2,660,189
     ----------------------------------------------------------------------------------------
     Class L                                                                      1,615,374
     ----------------------------------------------------------------------------------------
NET ASSET VALUE:
     Class A (and redemption price)                                                  $10.19
     ----------------------------------------------------------------------------------------
     Class B *                                                                        $9.95
     ----------------------------------------------------------------------------------------
     Class L **                                                                       $9.95
     ----------------------------------------------------------------------------------------

MAXIMUM PUBLIC OFFERING PRICE PER SHARE:
     Class A (net asset value plus 5.26% of net asset value per share)               $10.73
     ----------------------------------------------------------------------------------------
     Class L (net asset value plus 1.01% of net asset value per share)               $10.05
=============================================================================================
 *   REDEMPTION PRICE IS NAV OF CLASS B SHARES REDUCED BY A 5.00% CDSC IF SHARES ARE REDEEMED
     WITHIN ONE YEAR FROM PURCHASE (SEE NOTE 2).

 **  REDEMPTION PRICE IS NAV OF CLASS L SHARES REDUCED BY A 1.00% CDSC IF SHARES ARE REDEEMED
     WITHIN THE FIRST YEAR OF PURCHASE (SEE NOTE 2).



                       SEE NOTES TO FINANCIAL STATEMENTS.

  4  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders



STATEMENT OF OPERATIONS (UNAUDITED)      FOR THE SIX MONTHS ENDED APRIL 30, 2003



INVESTMENT INCOME:
                                                                             
     Dividends                                                                  $   336,129
     Interest                                                                         2,408
- ---------------------------------------------------------------------------------------------
     TOTAL INVESTMENT INCOME                                                        338,537
- ---------------------------------------------------------------------------------------------

EXPENSES:
     Management fee (Note 2)                                                        230,387
     Distribution fees (Note 7)                                                     229,144
     Shareholder servicing fees (Note 7)                                             47,603
     Shareholder communications (Note 7)                                             24,616
     Custody                                                                         17,856
     Audit and legal                                                                 14,480
     Registration fees                                                                7,240
     Directors' fees                                                                  5,837
     Other                                                                            9,412
- ---------------------------------------------------------------------------------------------
     TOTAL EXPENSES                                                                 586,575
- ---------------------------------------------------------------------------------------------
NET INVESTMENT LOSS                                                                (248,038)
- ---------------------------------------------------------------------------------------------

REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS (NOTE 3):
     Realized Loss From Security Transactions (excluding short-term securities):
        Proceeds from sales                                                      25,857,484
        Cost of securities sold                                                  33,343,670
- ---------------------------------------------------------------------------------------------
     NET REALIZED LOSS                                                           (7,486,186)
- ---------------------------------------------------------------------------------------------

     Change in Net Unrealized Depreciation of Investments:
        Beginning of period                                                     (10,290,175)
        End of period                                                              (716,148)
- ---------------------------------------------------------------------------------------------
     DECREASE IN NET UNREALIZED DEPRECIATION                                      9,574,027
- ---------------------------------------------------------------------------------------------
NET GAIN ON INVESTMENTS                                                           2,087,841
- ---------------------------------------------------------------------------------------------
INCREASE IN NET ASSETS FROM OPERATIONS                                          $ 1,839,803
=============================================================================================



                       SEE NOTES TO FINANCIAL STATEMENTS.

  5  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders




STATEMENTS OF CHANGES IN NET ASSETS

FOR THE SIX MONTHS ENDED APRIL 30, 2003 (UNAUDITED)
AND THE YEAR ENDED OCTOBER 31, 2002



                                                                    2003           2002
=============================================================================================
                                                                          
OPERATIONS:
     Net investment loss                                       $   (248,038)     $ (839,297)
     Net realized loss                                           (7,486,186)     (5,535,227)
     (Increase) decrease in net unrealized depreciation           9,574,027     (11,767,125)
- ---------------------------------------------------------------------------------------------
     INCREASE (DECREASE) IN NET ASSETS FROM OPERATIONS            1,839,803     (18,141,649)
- ---------------------------------------------------------------------------------------------

DISTRIBUTIONS TO SHAREHOLDERS FROM (NOTE 6):
     Net realized gains                                                  --      (1,075,678)
- ---------------------------------------------------------------------------------------------
     DECREASE IN NET ASSETS FROM DISTRIBUTIONS TO SHAREHOLDERS           --      (1,075,678)
- ---------------------------------------------------------------------------------------------

FUND SHARE TRANSACTIONS (NOTE 8):
     Net proceeds from sale of shares                             4,159,098      16,062,165
     Net asset value of shares issued for reinvestment of
       dividends                                                         --       1,025,003
     Cost of shares reacquired                                   (7,235,403)    (18,814,714)
- ---------------------------------------------------------------------------------------------
     DECREASE IN NET ASSETS FROM FUND SHARE TRANSACTIONS         (3,076,305)     (1,727,546)
- ---------------------------------------------------------------------------------------------
DECREASE IN NET ASSETS                                           (1,236,502)    (20,944,873)

NET ASSETS:
     Beginning of period                                         59,939,675      80,884,548
- ---------------------------------------------------------------------------------------------
     END OF PERIOD*                                             $58,703,173     $59,939,675
=============================================================================================
* Includes accumulated net investment loss of:                    $(252,218)        $(4,180)
=============================================================================================






                       SEE NOTES TO FINANCIAL STATEMENTS.

  6  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders


NOTES TO FINANCIAL STATEMENTS (UNAUDITED)

1. SIGNIFICANT ACCOUNTING POLICIES

The Smith Barney Health  Sciences Fund ("Fund"),  a separate  investment fund of
the Smith Barney  Sector  Series Inc.  ("Series"),  a Maryland  corporation,  is
registered  under  the  Investment  Company  Act  of  1940,  as  amended,  as  a
non-diversified,  open-end management investment company. The Series consists of
this  Fund and two other  separate  investment  funds:  Smith  Barney  Financial
Services Fund and Smith Barney  Technology  Fund.  The financial  statements and
financial  highlights for the other funds are presented in separate  shareholder
reports.

The  significant  accounting  policies  followed by the Fund are:  (a)  security
transactions are accounted for on trade date; (b) securities  traded in national
securities  markets are valued at the closing prices in the primary  exchange on
which they are traded;  securities listed or traded on certain foreign exchanges
or other  markets  whose  operations  are  similar to the U.S.  over-the-counter
market  (including  securities  listed on exchanges  where the primary market is
believed to be  over-the-counter)  and securities for which no sale was reported
on that date are valued at the mean between the bid and asked prices; securities
listed on the NASDAQ  National  Market  System for which market  quotations  are
available  are valued at the official  closing price or, if there is no official
closing price on that day, at the last sales price.  Securities which are listed
or traded on more than one  exchange or market are valued at the  quotations  on
the exchange or market  determined to be the primary market for such securities;
(c) securities  for which market  quotations are not available will be valued in
good  faith at fair  market  value by or under  the  direction  of the  Board of
Directors;  (d)  securities  maturing  within  60 days are  valued  at cost plus
accreted discount, or minus amortized premium, which approximates value; (e) the
accounting  records of the Fund are maintained in U.S.  dollars.  All assets and
liabilities  denominated in foreign  currencies are translated into U.S. dollars
based on the rate of exchange of such  currencies  against  U.S.  dollars on the
date of valuation.  Purchases and sales of  securities,  and income and expenses
are translated at the rate of exchange  quoted on the respective  date that such
transactions  are  recorded.  Differences  between  income  or  expense  amounts
recorded and collected or paid are adjusted when reported by the custodian;  (f)
interest income, adjusted for amortization of premium and accretion of discount,
is  recorded  on an  accrual  basis;  (g)  dividend  income is  recorded  on the
ex-dividend  date;  foreign dividends are recorded on the ex-dividend date or as
soon as  practical  after  the  Fund  determines  the  existence  of a  dividend
declaration  after  exercising  reasonable  due  diligence;  (h)  dividends  and
distributions  to shareholders  are recorded on the  ex-dividend  date; the Fund
distributes  dividends and capital gains, if any, annually;  (i) gains or losses
on the sale of securities  are  calculated by using the specific  identification
method;  (j) direct  expenses  are  charged to each class;  management  fees and
general Fund expenses are allocated on the basis of relative net assets; (k) the
Fund intends to comply with the  applicable  provisions of the Internal  Revenue
Code of 1986, as amended,  pertaining to regulated  investment  companies and to
make distributions of taxable income sufficient to relieve it from substantially
all Federal income and excise taxes; (l) the character of income and gains to be
distributed  in  accordance  with income tax  regulations  which may differ from
accounting  principles  generally accepted in the United States of America;  and
(m)  estimates  and  assumptions  are  required  to be  made  regarding  assets,
liabilities  and changes in net assets  resulting from operations when financial
statements are prepared. Changes in the economic environment,  financial markets
and any other parameters used in determining  these estimates could cause actual
results to differ.

In  addition,  the Fund may enter into  forward  exchange  contracts in order to
hedge against foreign currency risk. These contracts are marked-to-market daily,
by recognizing the difference between the contract exchange rate and the current
market  rate as an  unrealized  gain or  loss.  Realized  gains  or  losses  are
recognized when contracts are settled. The Fund from time to time may also enter
into options and/or futures contracts to hedge market risk.



  7  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders



NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

2. MANAGEMENT AGREEMENT AND OTHER TRANSACTIONS

Smith Barney Fund Management LLC ("SBFM"), an indirect  wholly-owned  subsidiary
of Citigroup  Inc.  ("Citigroup"),  acts as investment  manager to the Fund. The
management  fee is computed at an annual rate of 0.80% of the average  daily net
assets.  This fee is calculated  daily and paid monthly.  SBFM has delegated the
daily management of the Fund to Citi Fund Management Inc. ("CFM"),  an affiliate
of SBFM.  For services  provided to the Fund,  SBFM pays CFM a  subadvisory  fee
computed at an annual rate of 0.50% of the Fund's average daily net assets.

Citicorp Trust Bank, fsb. ("CTB"), another subsidiary of Citigroup,  acts as the
Fund's  transfer  agent.  PFPC  Global  Fund  Services  ("PFPC")  and  Primerica
Shareholder Services ("PSS"), another subsidiary of Citigroup, act as the Fund's
sub-transfer  agents.  CTB receives  account fees and asset-based fees that vary
according  to the size and type of  account.  PFPC and PSS are  responsible  for
shareholder  recordkeeping and financial processing for all shareholder accounts
and are paid by CTB.  For the six months  ended  April 30,  2003,  the Fund paid
transfer agent fees of $29,789 to CTB.

Citigroup  Global Markets Inc.  ("CGM"),  formerly known as Salomon Smith Barney
Inc., and PFS  Distributors,  Inc., both of which are subsidiaries of Citigroup,
act  as  the  Fund's   distributors.   In  addition,   CGM  and  certain   other
broker-dealers  continue  to sell Fund  shares to the  public as  members of the
selling  group.  For the six months ended April 30, 2003, CGM and its affiliates
did not receive any brokerage commissions.

There are maximum  initial  sales  charges of 5.00% and 1.00% for Class A shares
and L shares, respectively. There is a contingent deferred sales charge ("CDSC")
of 5.00% on Class B shares,  which applies if redemption  occurs within one year
from initial purchase and declines thereafter by 1.00% per year until no CDSC is
incurred.  Class L shares also have a 1.00% CDSC,  which  applies if  redemption
occurs  within the first year of purchase.  In  addition,  Class A shares have a
1.00%  CDSC,  which  applies  if  redemption  occurs  within  the first  year of
purchase.  This CDSC only applies to those  purchases  of Class A shares  which,
when  combined  with  current  holdings  of  Class A  shares,  equal  or  exceed
$1,000,000  in the  aggregate.  These  purchases  do not incur an initial  sales
charge.

For the six months ended April 30, 2003, CGM and its  affiliates  received sales
charges of approximately $40,000 and $2,000 on sales of the Fund's Class A and L
shares,  respectively.  In  addition,  for the six months  ended April 30, 2003,
CDSCs paid to CGM and its  affiliates  were  approximately  $41,000  for Class B
shares.

All officers  and one  Director of the Series are  employees of Citigroup or its
affiliates.

3. Investments

During the six months ended April 30, 2003,  the aggregate cost of purchases and
proceeds  from  sales  of   investments   (including   maturities  of  long-term
securities, but excluding short-term securities) were as follows:

================================================================================
Purchases                                                          $21,117,221
- --------------------------------------------------------------------------------
Sales                                                               25,857,484
================================================================================



  8  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders


NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

At April 30, 2003, the aggregate gross unrealized appreciation and depreciation
of investments for Federal income tax purposes were substantially as follows:

================================================================================
Gross unrealized appreciation                                      $ 4,561,784
Gross unrealized depreciation                                       (5,277,932)
- --------------------------------------------------------------------------------
Net unrealized depreciation                                        $  (716,148)
================================================================================

4. Repurchase Agreements

The Fund  purchases  (and its custodian  takes  possession  of) U.S.  government
securities  from  securities   dealers  subject  to  agreements  to  resell  the
securities to the sellers at a future date (generally, the next business day) at
an agreed upon higher repurchase price. The Fund requires continual  maintenance
of the market  value (plus  accrued  interest) of the  collateral  in amounts at
least equal to the repurchase price.

5. Concentration of Risk

The  Fund  normally  invests  at  least  80% of its  assets  in  health  related
investments.  As a result of this  concentration  policy, the Fund's investments
may be subject to greater risk and market  fluctuation  than a fund that invests
in securities representing a broader range of investment alternatives.

6. Distributions Paid to Shareholders by Class

                                        SIX MONTHS ENDED          YEAR ENDED
                                         APRIL 30, 2003        OCTOBER 31, 2002
================================================================================
NET REALIZED GAINS
Class A                                        --                $  261,497
Class B                                        --                   461,311
Class L                                        --                   352,870
- --------------------------------------------------------------------------------
Total                                          --                $1,075,678
================================================================================

7. Class Specific Expenses

Pursuant to a Distribution Plan, the Fund pays a service fee with respect to its
Class A, B and L shares  calculated  at the annual  rate of 0.25% of the average
daily net assets of each respective class. The Fund also pays a distribution fee
with respect to Class B and L shares  calculated  at the annual rate of 0.75% of
the  average  daily net assets of each class,  respectively.  For the six months
ended April 30, 2003, total  Distribution Plan fees incurred,  which are accrued
daily and paid monthly, were as follows:

                                           CLASS A       CLASS B        CLASS L
================================================================================
Distribution Plan Fees                     $19,613      $127,821        $81,710
================================================================================

For the six months ended April 30, 2003, total Shareholder Servicing fees were
as follows:

                                           CLASS A       CLASS B        CLASS L
================================================================================
Shareholder Servicing Fees                 $12,976       $21,135        $13,492
================================================================================

For the six months ended April 30, 2003, total Shareholder Communication
expenses were as follows:

                                           CLASS A       CLASS B        CLASS L
================================================================================
Shareholder Communication Expenses          $6,844       $11,019         $6,753
================================================================================


  9  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders


NOTES TO FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

8. CAPITAL SHARES

At April 30, 2003, the Fund had 750 million  shares of capital stock  authorized
with a par value of $0.001 per share. The Fund has the ability to issue multiple
classes of shares. Each share of a class represents an identical interest in the
Fund and has the same  rights,  except  that each class bears  certain  expenses
specifically related to the distribution of its shares.

Transactions in shares of each class were as follows:




                                                 SIX MONTHS ENDED                        YEAR ENDED
                                                  APRIL 30, 2003                     OCTOBER 31, 2002
                                            --------------------------           -------------------------
                                              SHARES           AMOUNT               SHARES        AMOUNT
============================================================================================================
                                                                                   
CLASS A
Shares sold                                   200,422      $  1,977,085            507,533     $ 5,868,322
Shares issued on reinvestment                      --                --             19,429         253,154
Shares reacquired                            (267,161)       (2,635,530)          (433,256)     (4,948,112)
- ------------------------------------------------------------------------------------------------------------
Net Increase (Decrease)                       (66,739)     $   (658,445)            93,706     $ 1,173,364
============================================================================================================
CLASS B
Shares sold                                   180,974      $  1,747,079            643,297     $ 7,469,050
Shares issued on reinvestment                      --                --             33,569         431,364
Shares reacquired                            (243,343)       (2,331,621)          (673,410)     (7,315,315)
- ------------------------------------------------------------------------------------------------------------
Net Increase (Decrease)                       (62,369)     $   (584,542)             3,456     $   585,099
============================================================================================================
CLASS L
Shares sold                                    44,993      $    434,934            231,847     $ 2,724,793
Shares issued on reinvestment                      --                --             26,497         340,485
Shares reacquired                            (237,030)       (2,268,252)          (595,558)     (6,551,287)
- ------------------------------------------------------------------------------------------------------------
Net Decrease                                 (192,037)     $ (1,833,318)          (337,214)    $(3,486,009)
============================================================================================================


9. SUBSEQUENT EVENT

On January 29,  2003,  the Board of  Directors  of the Series,  on behalf of the
Smith Barney  Biotechnology Fund  ("Biotechnology  Fund"), a separate investment
fund of the  Series,  approved a proposed  reorganization  pursuant to which the
Fund  would  acquire  the  assets  and  assume  the  stated  liabilities  of the
Biotechnology Fund in exchange for shares of the Fund. This  reorganization will
allow  Biotechnology  Fund shareholders to maintain an investment in a fund with
the same investment objective and substantially  similar investment policies. On
May  7,  2003,  the  shareholders  of  the   Biotechnology   Fund  approved  the
reorganization  of the  Biotechnology  Fund into the Fund. The effective date of
the reorganization was May 9, 2003.




 10  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders


FINANCIAL HIGHLIGHTS


FOR A SHARE OF EACH CLASS OF CAPITAL STOCK OUTSTANDING THROUGHOUT EACH YEAR
ENDED OCTOBER 31, UNLESS OTHERWISE NOTED:




CLASS A SHARES                                             2003(1)(2)        2002(2)            2001            2000(3)
==========================================================================================================================
                                                                                                    
NET ASSET VALUE, BEGINNING OF PERIOD                      $ 9.84             $12.72            $14.49           $11.40
- --------------------------------------------------------------------------------------------------------------------------
INCOME (LOSS) FROM OPERATIONS:
   Net investment loss(4)                                  (0.02)             (0.07)            (0.08)           (0.04)
   Net realized and unrealized gain (loss)                  0.37              (2.64)            (1.29)            3.13
- --------------------------------------------------------------------------------------------------------------------------
Total Income (Loss) From Operations                         0.35              (2.71)            (1.37)            3.09
- --------------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS FROM:
   Net realized gains                                         --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
Total Distributions                                           --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                           $ 10.19            $  9.84           $ 12.72          $ 14.49
- --------------------------------------------------------------------------------------------------------------------------
TOTAL RETURN                                                3.56%++          (21.65)%           (9.83)%          27.11%++
- --------------------------------------------------------------------------------------------------------------------------
NET ASSETS, END OF PERIOD (000S)                         $16,152            $16,251           $19,806          $16,980
- --------------------------------------------------------------------------------------------------------------------------
RATIOS TO AVERAGE NET ASSETS:

   Expenses(4)(5)                                           1.49%+             1.49%             1.50%            1.52%+
   Net investment loss                                     (0.32)+            (0.58)            (0.63)           (0.67)+
- --------------------------------------------------------------------------------------------------------------------------
PORTFOLIO TURNOVER RATE                                       37%                26%               34%              26%
==========================================================================================================================


CLASS B SHARES                                             2003(1)(2)        2002(2)            2001            2000(3)
==========================================================================================================================
NET ASSET VALUE, BEGINNING OF PERIOD                     $  9.64            $ 12.56           $ 14.42          $ 11.40
- --------------------------------------------------------------------------------------------------------------------------
INCOME (LOSS) FROM OPERATIONS:
   Net investment loss(4)                                  (0.05)             (0.15)            (0.18)           (0.09)
   Net realized and unrealized gain (loss)                  0.36              (2.60)            (1.28)            3.11
- --------------------------------------------------------------------------------------------------------------------------
Total Income (Loss) From Operations                         0.31              (2.75)            (1.46)            3.02
- --------------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS FROM:
   Net realized gains                                         --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
Total Distributions                                           --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                           $  9.95            $  9.64           $ 12.56          $ 14.42
- --------------------------------------------------------------------------------------------------------------------------
TOTAL RETURN                                                3.22%++          (22.25)%          (10.51)%          26.49%++
- --------------------------------------------------------------------------------------------------------------------------
NET ASSETS, END OF PERIOD (000S)                         $26,475            $26,258           $34,146          $28,694
- --------------------------------------------------------------------------------------------------------------------------
RATIOS TO AVERAGE NET ASSETS:
   Expenses(4)(6)                                           2.24%+             2.24%             2.25%            2.26%+
   Net investment loss                                     (1.07)+            (1.33)            (1.38)           (1.41)+
- --------------------------------------------------------------------------------------------------------------------------
PORTFOLIO TURNOVER RATE                                       37%                26%               34%              26%
==========================================================================================================================


(1)  FOR THE SIX MONTHS ENDED APRIL 30, 2003 (UNAUDITED).

(2)  PER SHARE AMOUNTS HAVE BEEN CALCULATED USING THE MONTHLY AVERAGE SHARES
     METHOD.

(3)  FOR THE PERIOD FROM FEBRUARY 28, 2000 (INCEPTION DATE) TO OCTOBER 31, 2000.

(4)  THE MANAGER WAIVED A PORTION OF ITS FEES FOR THE YEAR ENDED OCTOBER 31,
     2001 AND FOR THE PERIOD ENDED OCTOBER 31, 2000. IF SUCH FEES WERE NOT
     WAIVED, THE PER SHARE INCREASES TO NET INVESTMENT LOSS AND THE ACTUAL
     EXPENSE RATIOS WOULD HAVE BEEN AS FOLLOWS:




                                            Per Share Increases to                   Expense Ratios
                                              Net Investment Loss                  Without Fee Waivers
                                           ------------------------             -----------------------
                                            2001              2000               2001              2000
                                           ------            ------             ------            ------
                                                                                      
     Class A Shares                        $0.01             $0.00*              1.53%            1.94%+
     Class B Shares                         0.00*             0.01               2.28             2.68+



(5)  AS A RESULT OF VOLUNTARY EXPENSE LIMITATIONS, THE RATIO OF EXPENSES TO
     AVERAGE NET ASSETS WILL NOT EXCEED 1.50% FOR CLASS A SHARES.

(6)  AS A RESULT OF VOLUNTARY EXPENSE LIMITATIONS, THE RATIO OF EXPENSES TO
     AVERAGE NET ASSETS WILL NOT EXCEED 2.25% FOR CLASS B SHARES.

 *   AMOUNT REPRESENTS LESS THAN $0.01 PER SHARE.

++   TOTAL RETURN IS NOT ANNUALIZED, AS IT MAY NOT BE REPRESENTATIVE OF THE
     TOTAL RETURN FOR THE YEAR.

+    ANNUALIZED.


 11  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders


 FINANCIAL HIGHLIGHTS (CONTINUED)

FOR A SHARE OF EACH CLASS OF CAPITAL STOCK OUTSTANDING THROUGHOUT EACH YEAR
ENDED OCTOBER 31, UNLESS OTHERWISE NOTED:



CLASS L SHARES                                            2003(1)(2)         2002(2)            2001             2000(3)
==========================================================================================================================
                                                                                                    
NET ASSET VALUE, BEGINNING OF PERIOD                       $9.64             $12.56            $14.42           $11.40
- --------------------------------------------------------------------------------------------------------------------------
INCOME (LOSS) FROM OPERATIONS:
   Net investment loss(4)                                  (0.05)             (0.15)            (0.18)           (0.09)
   Net realized and unrealized gain (loss)                  0.36              (2.60)            (1.28)            3.11
- --------------------------------------------------------------------------------------------------------------------------
Total Income (Loss) From Operations                         0.31              (2.75)            (1.46)            3.02
- --------------------------------------------------------------------------------------------------------------------------
LESS DISTRIBUTIONS FROM:
   Net realized gains                                         --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
Total Distributions                                           --              (0.17)            (0.40)              --
- --------------------------------------------------------------------------------------------------------------------------
NET ASSET VALUE, END OF PERIOD                             $9.95             $ 9.64            $12.56           $14.42
- --------------------------------------------------------------------------------------------------------------------------
TOTAL RETURN                                                3.22%++          (22.25)%          (10.51)%          26.49%++
- --------------------------------------------------------------------------------------------------------------------------
NET ASSETS, END OF PERIOD (000S)                         $16,076            $17,431           $26,932          $26,273
- --------------------------------------------------------------------------------------------------------------------------
RATIOS TO AVERAGE NET ASSETS:
   Expenses(4)(5)                                           2.24%+             2.24%             2.25%            2.27%+
   Net investment loss                                     (1.06)+            (1.33)            (1.37)           (1.42)+
- --------------------------------------------------------------------------------------------------------------------------
PORTFOLIO TURNOVER RATE                                       37%                26%               34%              26%
==========================================================================================================================


(1)  FOR THE SIX MONTHS ENDED APRIL 30, 2003 (UNAUDITED).

(2)  PER SHARE AMOUNTS HAVE BEEN CALCULATED USING THE MONTHLY AVERAGE SHARES
     METHOD.

(3)  FOR THE PERIOD FROM FEBRUARY 28, 2000 (INCEPTION DATE) TO OCTOBER 31, 2000.

(4)  THE MANAGER WAIVED A PORTION OF ITS FEES FOR THE YEAR ENDED OCTOBER 31,
     2001 AND FOR THE PERIOD ENDED OCTOBER 31, 2000. IF SUCH FEES WERE NOT
     WAIVED, THE PER SHARE INCREASES TO NET INVESTMENT LOSS AND THE ACTUAL
     EXPENSE RATIOS WOULD HAVE BEEN AS FOLLOWS:



                                            Per Share Increases to                   Expense Ratios
                                              Net Investment Loss                  Without Fee Waivers
                                           ------------------------             -----------------------
                                            2001              2000               2001              2000
                                           ------            ------             ------            ------
                                                                                      
    Class L Shares                         $0.00*            $0.01               2.28%            2.68%+


(5)  AS A RESULT OF VOLUNTARY EXPENSE LIMITATIONS, THE RATIO OF EXPENSES TO
     AVERAGE NET ASSETS WILL NOT EXCEED 2.25% FOR CLASS L SHARES.

  *  AMOUNT REPRESENTS LESS THAN $0.01 PER SHARE.

 ++  TOTAL RETURN IS NOT ANNUALIZED, AS IT MAY NOT BE REPRESENTATIVE OF THE
     TOTAL RETURN FOR THE YEAR. + ANNUALIZED.




 12  SMITH BARNEY SECTOR SERIES INC. | 2003 Semi-Annual Report to Shareholders




SMITH BARNEY
HEALTH SCIENCES FUND

     DIRECTORS
     Herbert Barg
     Dwight B. Crane
     Burt N. Dorsett
     R. Jay Gerken, Chairman
     Elliot S. Jaffe
     Stephen E. Kaufman Joseph J. McCann
     Cornelius C. Rose, Jr.

     OFFICERS
     R. Jay Gerken
     President and Chief
     Executive Officer

     Lewis E. Daidone
     Senior Vice President and
     Chief Administrative Officer

     Richard L. Peteka
     Chief Financial Officer
     and Treasurer

     Kaprel Ozsolak
     Controller

     Christina T. Sydor
     Secretary

     INVESTMENT MANAGER
     Smith Barney Fund Management LLC

     INVESTMENT SUB-ADVISER
     Citi Fund Management Inc.

     DISTRIBUTORS
     Citigroup Global Markets Inc.
     PFS Distributors, Inc.

     CUSTODIAN
     State Street Bank and
       Trust Company

     TRANSFER AGENT
     Citicorp Trust Bank, fsb.
     125 Broad Street, 11th Floor
     New York, New York 10004

     SUB-TRANSFER AGENTS
     PFPC Global Fund Services
     P.O. Box 9699
     Providence, Rhode Island
     02940-9699

     Primerica Shareholder Services
     P.O. Box 9662
     Providence, Rhode Island
     02940-9662




SMITH BARNEY HEALTH SCIENCES FUND
- --------------------------------------------------------------------------------

This report is submitted for the general information of the shareholders of
Smith Barney Sector Series Inc. -- Smith Barney Health Sciences Fund, but it may
also be used as sales literature when preceded or accompanied by the current
Prospectus, which gives details about charges, expenses, investment objectives
and operating policies of the Fund. If used as sales material after July 31,
2003, this report must be accompanied by performance information for the most
recently completed calendar quarter.

SMITH BARNEY HEALTH SCIENCES FUND
Smith Barney Mutual Funds
125 Broad Street
10th Floor, MF-2
New York, New York 10004

For complete information on any Smith Barney Mutual Funds, including management
fees and expenses, call or write your financial professional for a free
prospectus. Read it carefully before you invest or send money.

WWW.SMITHBARNEYMUTUALFUNDS.COM

(C)2003 Citigroup Global Markets Inc.
Member NASD, SIPC

FD02553 6/03                                                             03-4964



ITEM 2.  CODE OF ETHICS.

         Not applicable.

ITEM 3.  AUDIT COMMITTEE FINANCIAL EXPERT.

         Not applicable.

ITEM 4.  PRINCIPAL ACCOUNTANT FEES AND SERVICES.

         Not applicable.

ITEM 5.  AUDIT COMMITTEE OF LISTED REGISTRANTS.

         Not applicable.

ITEM 6.  [RESERVED]

ITEM 7.  DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END
         MANAGEMENT INVESTMENT COMPANIES.

         Not applicable.

ITEM 8.  [RESERVED]

ITEM 9.  CONTROLS AND PROCEDURES.

        (a) The registrant's principal executive officer and principal financial
            officer have concluded that the registrant's disclosure controls and
            procedures (as defined in Rule 30a-2(c) under the Investment Company
            Act of 1940, as amended) are effective based on their evaluation of
            the disclosure controls and procedures as of a date within 90 days
            of the filing date of this document.

        (b) In the last 90 days, there have been no significant changes in the
            Registrant's internal controls or in other factors that could
            significantly affect these controls.

ITEM 10. EXHIBITS.

        (a) Not applicable.

        (b) Attached hereto.

        Exhibit 99.CERT       Certifications pursuant to section 302 of the
                              Sarbanes-Oxley Act of 2002

        Exhibit 99.906CERT    Certifications pursuant to Section 906 of
                              the Sarbanes-Oxley Act of 2002

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this Report to be
signed on its behalf by the undersigned, there unto duly authorized.




SMITH BARNEY SECTOR SERIES INC.

By:      /s/ R. Jay Gerken
         R. Jay Gerken
         Chief Executive Officer of
         Smith Barney Sector Series Inc.

Date:

     Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed below by the
following persons on behalf of the registrant and in the capacities and on the
dates indicated.

By:      /s/ R. Jay Gerken
         (R. Jay Gerken)
         Chief Executive Officer of
         Smith Barney Sector Series Inc.

Date:

By:      /s/ RICHARD PETEKA
         Chief Financial Officer of
         Smith Barney Sector Series Inc.

Date: