UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 11-K

(Mark One)

[X]  ANNUAL REPORT  PURSUANT TO SECTION 15(d) OF THE SECURITIES  EXCHANGE ACT OF
     1934

For the fiscal year ended December 31, 1999


                                       OR


[ ]  TRANSITION  REPORT  PURSUANT TO SECTION 15(d) OF THE SECURITIES  EXCHANGE
     ACT OF 1934

For the transition period from                     to __________
                               -------------------



                         COMMISSION FILE NUMBER 1-11377




                         CINERGY CORP. UNION EMPLOYEES'
                             SAVINGS INCENTIVE PLAN
                            (Full title of the plan)





                                  CINERGY CORP.

          (Name of issuer of the securities held pursuant to the plan)


                             139 EAST FOURTH STREET
                             CINCINNATI, OHIO 45202

                    (Address of principal executive offices)








                                      CINERGY CORP. UNION EMPLOYEES'
                                          SAVINGS INCENTIVE PLAN

                                    FINANCIAL STATEMENTS AND EXHIBITS

                                                                       PAGE NO.
                                                                       -------

(a)  Financial Statements

     Report of Independent Public Accountants                              3

     Statements of Net Assets Available for Benefits
     as of December 31, 1999 and 1998                                      4

     Statement of Changes in Net Assets Available for Benefits
     for the Year Ended December 31, 1999                                  5

     Notes to Financial Statements                                       6-10

     Financial Statement Schedules (As required by the Employee
      Retirement Income Security Act):


             Schedule I - Schedule of Assets Held for
              Investment Purposes - at End of Year
              December 31, 1999                                           11

(b)  Exhibit 23 - Consent of Independent Public Accountants













REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS

To the Plan Administrator of the
   Cinergy Corp. Union Employees' Savings Incentive Plan:

We have audited the accompanying statements of net assets available for benefits
of the CINERGY CORP. UNION EMPLOYEES'  SAVINGS INCENTIVE PLAN as of December 31,
1999 and 1998, and the related  statement of changes in net assets available for
benefits for the year ended December 31, 1999.  These  financial  statements and
the schedule referred to below are the  responsibility of the Plan's management.
Our  responsibility  is to express an opinion on these financial  statements and
the schedule based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable  assurance about whether the financial  statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting  the amounts and  disclosures in the financial  statements.  An audit
also includes assessing the accounting principles used and significant estimates
made by  management,  as well as  evaluating  the  overall  financial  statement
presentation.  We believe  that our audits  provide a  reasonable  basis for our
opinion.

In our opinion,  the financial  statements  referred to above present fairly, in
all material  respects,  the net assets available for benefits of the Plan as of
December  31,  1999,  and 1998,  and the  changes  in net assets  available  for
benefits for the year ended  December  31, 1999 in  conformity  with  accounting
principles generally accepted in the United States.

Our audit was  performed  for the  purpose  of  forming  an opinion on the basic
financial statements taken as a whole. The supplemental schedule (Schedule I) is
presented for the purpose of  additional  analysis and is not a required part of
the basic financial statements but is supplementary  information required by the
Department of Labor's Rules and Regulations  for Reporting and Disclosure  under
the Employee  Retirement Income Security Act of 1974. The supplemental  schedule
has been subjected to the auditing  procedures applied in our audit of the basic
financial  statements  and, in our  opinion,  is fairly  stated in all  material
respects in relation to the basic financial statements taken as a whole.

                                                             ARTHUR ANDERSEN LLP

Cincinnati, Ohio,
June 26, 2000











              CINERGY CORP. UNION EMPLOYEES' SAVINGS INCENTIVE PLAN

                 STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS
                        AS OF DECEMBER 31, 1999 AND 1998



                                                        1999            1998
                                                    ------------    ------------
ASSETS:

  Investments at fair value (See Notes 4 and 5)     $167,360,381    $191,754,949

  Employer's contribution receivable                   1,914,099       1,370,842
                                                    ------------    ------------

     Net assets available for benefits              $169,274,480    $193,125,791
                                                    ============    ============







                 See accompanying notes to financial statements.








              CINERGY CORP. UNION EMPLOYEES' SAVINGS INCENTIVE PLAN

            STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS
                      FOR THE YEAR ENDED DECEMBER 31, 1999

ADDITIONS:
  Additions to net assets attributed to:
     Investment income:
          Net depreciation in fair value of investments          $(40,270,884)
           (See Notes 4 and 5)
          Interest and dividends                                   12,448,748
                                                                 ------------
                                                                  (27,822,136)

     Contributions:
        Participant                                                 9,026,917
        Employer                                                    4,754,808
        Rollover                                                      101,622
                                                                 ------------
                                                                   13,883,347
                                                                 ------------
            Total additions                                       (13,938,789)


DEDUCTIONS:
 Deductions from net assets attributed to:
  Benefits paid to participants                                    (7,364,549)
                                                                 ------------
       Total deductions                                            (7,364,549)
                                                                 ------------

Net decrease prior to transfers                                   (21,303,338)
Interplan transfers                                                (2,547,973)
                                                                 ------------
                                                                  (23,851,311)

Net assets available for benefits:
Beginning of year                                                 193,125,791
                                                                 ------------
End of year                                                      $169,274,480
                                                                 ============



                 See accompanying notes to financial statements.








                         CINERGY CORP. UNION EMPLOYEES'
                             SAVINGS INCENTIVE PLAN


                          NOTES TO FINANCIAL STATEMENTS
                           DECEMBER 31, 1999 AND 1998

(1)  PLAN DESCRIPTION-
     ----------------

     The following  description of the Cinergy Corp.  Union  Employees'  Savings
     Incentive Plan (the Plan) provides only general  information.  Participants
     should refer to the Plan  Agreement for a more complete  description of the
     Plan's provisions.

     (a)  GENERAL--The  Plan  is  a  defined   contribution  plan  covering  all
          employees of Cinergy Corp.'s subsidiaries (collectively,  the Company)
          who  are   represented   by  the   following   collective   bargaining
          organizations:


          * The Independent Utilities Union
          * The International Brotherhood of Electrical Workers, Local 1347
          * The United Steelworkers of America, Local 12049 and Local 14214

          The  Plan  is  administered  by the  Cinergy  Benefits  Committee  and
          trusteed by the Fidelity Management Trust Company. The Plan is subject
          to the provisions of the Employee  Retirement  Income  Security Act of
          1974 (ERISA). The administrative  expenses of the Plan are paid by the
          Company.  Reference  should  be made to the Plan  document  for a more
          complete description of the Plan's provisions.

          The Cinergy Corp. Union Employees' Savings Incentive Plan was formerly
          The Cincinnati Gas & Electric  Company  Savings  Incentive Plan.   The
          Plan's name change was effective January 1, 1998.

     (b)  CONTRIBUTIONS--Under  the Plan,  participants may contribute up to 15%
          of annual pretax compensation,  as defined in the Plan. In addition, a
          participant may make after-tax  contributions to the Plan which,  when
          combined  with pretax  contributions,  may not exceed 15% of base pay.
          Pretax and after-tax contributions are subject to certain limitations.
          The pretax and after-tax contributions are invested by the trustee, as
          directed  by  each  participant,  in one  or  more  investment  funds,
          including the Cinergy Common Stock Fund.

          The  Company  matches 60% of the first 5% of base pay  contributed  by
          each  participant.  An additional  incentive match of up to 40% of the
          first 5% of base pay that a participant contributes may be contributed
          at the  discretion  of the  Company's  board of  directors.  For those
          employees who do not contribute to the Plan,  the Company  contributes
          an incentive  match assuming the employee  contributed 1% of base pay.
          All employer  contributions are invested by the trustee in the Cinergy
          Common  Stock  Fund.  The  employer  contributions  must remain in the
          Cinergy Common Stock Fund until the participant reaches age 50 and are
          shown in Note 4 as "Non-participant Directed" funds until the employee
          elects to transfer the funds to another investment option.

     (c)  VESTING--Participants  are immediately vested in all contributions and
          earnings thereon.

     (d)  PARTICIPANT ACCOUNTS--Each  participant's account is credited with the
          participant's   contribution   and   allocation   of   the   Company's
          contribution   and  Plan  earnings.   Allocations  are  based  on  the
          participant's account balance or contribution percentage as defined in
          the Plan  document.  The benefit to which a participant is entitled is
          the  benefit  that  can be  provided  from  the  participant's  vested
          account.

     (e)  PAYMENT OF  BENEFITS--Participants  are generally  eligible to receive
          distributions  of assets from the Plan upon  termination of employment
          (including retirement),  death, or disability.  Distributions are paid
          in a lump sum for vested benefits of $5,000 or less. Distributions are
          paid in a lump sum or up to ten annual  installments  (at the election
          of the participant)  for vested benefits  greater than $5,000.  Active
          participants are also eligible to apply to the Plan  administrator for
          "hardship"  withdrawals  from their pretax account in accordance  with
          Plan provisions.


     (f)  PARTICIPANT  LOANS--Subject to certain  limitations,  participants may
          apply for loans from their pretax  account  balances.  Interest on the
          loans is set at the prime rate plus 1/2% at the time of borrowing, and
          the loans are secured by the balance in the participant's account. The
          loans  are to be  repaid  within 54  months  through  regular  payroll
          deductions.


(2)  SIGNIFICANT ACCOUNTING POLICIES-
     -------------------------------

     (a)  BASIS OF ACCOUNTING--The financial statements of the Plan are prepared
          under the accrual method of accounting.

     (b)  INVESTMENT VALUATION AND INCOME RECOGNITION--Investments are stated at
          fair value.  Shares of registered  investment  companies are valued at
          quoted redemption prices which represent the net asset value of shares
          held by the Plan at  year-end.  Cinergy  common stock is valued at its
          quoted  market  price.  Participant  loans are  valued at cost,  which
          approximates fair value.


          Purchases and sales of securities are recorded on a trade-date  basis.
          Interest  income is  recorded  on the  accrual  basis.  Dividends  are
          recorded on the ex-dividend date.

          Transfers of assets  between the Plan and The Cinergy Corp.  Non-Union
          Employees' 401(k) Plan occur as a result of changes in employee status
          between  the  union  classification  and  the  exempt  and  non-exempt
          classifications.  Such transfers are reflected as interplan  transfers
          on the statement of changes in net assets available for benefits.

          A  participant  may  elect  or  change  investment  funds  and/or  the
          percentages in which contributions will be allocated at any time.

     (c)  USE  OF   ESTIMATES--The   preparation  of  financial   statements  in
          conformity  with generally  accepted  accounting  principles  requires
          management to make estimates and assumptions  that affect the reported
          amounts of assets and liabilities and changes therein,  and disclosure
          of  contingent  assets and  liabilities  at the date of the  financial
          statements. Actual results could differ from those estimates.

     (d)  PAYMENT OF BENEFITS--Benefits are recorded when paid.


(3)  ACCOUNTING CHANGE-
     ------------------

     The Accounting  Standards  Executive Committee issued Statement of Position
     99-3,  "Accounting for and Reporting of Certain Defined  Contribution  Plan
     Investments and Other Disclosure  Matters" (SOP 99-3), which eliminates the
     requirement    for   a    defined    contribution    plan    to    disclose
     participant-directed investment programs. As required by SOP 99-3, the Plan
     adopted SOP 99-3 for the 1999 financial statements and reclassified certain
     amounts   in   the   1998    financial    statements   to   eliminate   the
     participant-directed fund investment program disclosures.

(4)  NON-PARTICIPANT DIRECTED INVESTMENTS-
     -------------------------------------

     Information  about the net assets  and the  significant  components  of the
     changes in net assets relating to the non-participant  directed investments
     is as follows:

                                                       DECEMBER 31,
                                                      ------------
                                               1999                  1998
                                            -----------          -----------
NET ASSETS:

  Cinergy common stock                      $40,068,972          $51,611,340
                                            ===========          ===========




                                                 YEAR ENDED DECEMBER 31, 1999

Changes in net assets:
  Contributions                                            $4,754,808
  Dividends                                                 2,670,276
  Net appreciation                                        (16,440,844)
  Benefits paid to participants                            (1,064,594)
  Transfers to participant-directed investments              (748,420)
  Interplan transfers                                        (713,594)
                                                         ------------
                                                         $(11,542,368)
                                                         ============

(5)  INVESTMENTS-
     -----------

     The following investments exceed 5% of net assets available for benefits as
     of December 31, 1999 and 1998:

                                                1999                   1998
                                            ------------           ------------
     Cinergy Common Stock Fund              $105,435,317           $138,460,654
     Fidelity Magellan Fund                   21,300,150             15,024,006*
     Fidelity Equity Income Fund              19,067,953             19,164,991*


              * represents less than 5% of total net assets

     During  1999,  the  Plan's  investments  (including  gains  and  losses  on
     investments  bought and sold, as well as held during the year)  depreciated
     in value by $40,270,884 as follows:

              Mutual funds                              $  2,198,972
              Common stock                               (42,469,856)
                                                        ------------
                                                        $(40,270,884)
                                                        ============

(6)  FEDERAL INCOME TAX STATUS-
     -------------------------

     The Internal Revenue Service has determined and informed the Plan by letter
     dated  January 5, 1995,  that the Plan and  related  trust are  designed in
     accordance with applicable sections of the Internal Revenue Code (IRC). The
     Plan has been amended since receiving the  determination  letter.  However,
     the Plan  administrator  and the Plan's legal counsel believe that the Plan
     is  designed  and is  currently  being  operated  in  compliance  with  the
     applicable provisions of the IRC.


(7)  RECONCILIATION OF FINANCIAL STATEMENTS TO FORM 5500-
     ---------------------------------------------------

     The following is a reconciliation  of net assets available for benefits per
     the financial statements to the Form 5500:

                                                           DECEMBER 31,
                                                   ----------------------------

                                                       1999            1998
                                                   ------------    ------------

     Net assets per the financial statements       $169,274,480    $193,125,791
     Amounts allocated to withdrawing participants       (5,109)       (162,413)
                                                   ------------    ------------
     Net assets per Form 5500                      $169,269,371    $192,963,378
                                                   ============    ============


     The following is a reconciliation  of benefits paid to participants per the
     financial statements to Form 5500:

                                                                  YEAR ENDED
                                                               DECEMBER 31, 1999
                                                               -----------------

     Benefits paid to participants per the financial statements    $7,364,549
      Add:  Amounts allocated to withdrawing participants at
       December 31, 1999                                                5,109
      Less:  Amounts allocated to withdrawing participants at
       December 31, 1998                                             (162,413)
                --- ----                                           ----------
     Benefits paid to participants per Form 5500                   $7,207,245
                                                                   ==========


     Amounts allocated to withdrawing participants are recorded on Form 5500 for
     distributions  that have been  processed  and approved for payment prior to
     December 31 but not yet paid as of that date.

(8)  PLAN TERMINATION-
     ----------------

     Although  it has not  expressed  any intent to do so, the  Company  has the
     right under the Plan to discontinue  its  contributions  at any time and to
     terminate the Plan subject to the provisions of ERISA.

(9)  RELATED PARTY TRANSACTIONS-
     --------------------------

     Certain Plan  investments  are shares of mutual  funds  managed by Fidelity
     Investments. Fidelity Investments is the Trustee as defined by the Plan and
     therefore,  these transactions qualify as  party-in-interest  transactions.
     The  Cinergy  Corp.  Common  Stock  Fund  holds  common  stock  of the plan
     administrator  as defined  by the Plan and  therefore,  these  transactions
     qualify as  party-in-interest  transactions.  Finally, the Participant Loan
     Fund  holds  loans  from  participants  in the  Plan and  therefore,  these
     transactions qualify as party-in-interest transactions.










                                                                                                                         SCHEDULE I
                         CINERGY CORP. UNION EMPLOYEES'
                             SAVINGS INCENTIVE PLAN

                                 EIN: 31-0240030
                                PLAN NUMBER: 002

          Schedule 4i- Schedule of Assets Held for Investment Purposes
                        At End of Year December 31, 1999

                                                                                                              

IDENTITY OF ISSUER, BORROWER,       DESCRIPTION OF INVESTMENT, INCLUDING MATURITY DATE,
  LESSOR, OR SIMILAR PARTY        RATE OF INTEREST, COLLATERAL, AND PAR OR MATURITY VALUE              COST            CURRENT VALUE
- ----------------------------      -------------------------------------------------------          ------------        -------------

*  Cinergy Corp.                  Common Stock                                                     $133,423,123         $105,435,317
*  Fidelity Investments           Magellan Fund                                                      16,603,998           21,300,150
*  Fidelity Investments           Equity Income Fund                                                 16,461,456           19,067,953
*  Fidelity Investments           U.S. Bond Index Fund                                                2,165,043            2,080,560
*  Fidelity Investments           Low-Priced Stock Fund                                               1,712,063            1,575,896
*  Fidelity Investments           Diversified International Stock Fund                                  981,030            1,333,313
*  Fidelity Investments           Freedom Income Fund                                                   166,797              172,672
*  Fidelity Investments           Freedom 2000 Fund                                                     737,348              799,966
*  Fidelity Investments           Freedom 2010 Fund                                                     977,503            1,084,545
*  Fidelity Investments           Freedom 2020 Fund                                                     400,340              470,128
*  Fidelity Investments           Freedom 2030 Fund                                                     323,541              377,316
   Fidelity Investments           Blue Chip Fund                                                      1,005,367            1,162,637
   Fidelity Investments           Spartan U.S. Equity Fund                                              606,697              647,788
   Franklin Investments           Small Cap Growth Fund                                                 597,752              735,083
*  Fidelity Investments           Retirement Money Market Fund                                        3,295,083            3,295,083
*  Various plan participants      Participant loans (interest rates ranging from 6.50-9.50%)          7,821,974            7,821,974
                                                                                                   ------------         ------------
           Total assets held for investment purposes                                               $187,279,115         $167,360,381
                                                                                                   ============         ============

*  Denotes a party-in-interest
<FN>
                See accompanying notes to financial statements.

</FN>









                                   SIGNATURES

Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the Plan
Committee  has duly caused this annual  report to be signed on its behalf by the
undersigned hereunto duly authorized.


                         CINERGY CORP. UNION EMPLOYEES'
                             SAVINGS INCENTIVE PLAN
                             ----------------------

                              By /s/ DARLENE HUGHES
                                     --------------
                                     Darlene Hughes
                                   Plan Administrator


June 26, 2000










                                                                      EXHIBIT 23


                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent  public  accountants,  we hereby consent to the  incorporation by
reference  of our report  dated June 26, 2000  included in the Annual  Report on
Form 11-K for the year  ended  December  31,  1999 of the  Cinergy  Corp.  Union
Employees'  Savings  Incentive  Plan,  into  Cinergy  Corp.'s  previously  filed
Registration Statement File No. 33-55293.

                                                             ARTHUR ANDERSEN LLP


Cincinnati, Ohio
June 26, 2000