Exhibit 99.1

    CIMAREX ENERGY CO. ANNOUNCES CASH OFFERS TO ACQUIRE NOTES ASSUMED IN THE
                      MAGNUM HUNTER RESOURCES, INC. MERGER

    DENVER, July 6 /PRNewswire-FirstCall/ -- Cimarex Energy Co. (NYSE: XEC)
today initiated offers to purchase for cash any and all of its outstanding 9.60%
Senior Notes due 2012 (the 9.60% Notes) and any and all of its outstanding
Floating Rate Convertible Senior Notes due 2023 (the Convertible Notes). The
9.60% Senior Notes and the Convertible Notes were originally issued by Magnum
Hunter Resources, Inc. (MHR).

    On June 7, 2005, a wholly-owned subsidiary of Cimarex Energy Co. (Cimarex)
merged with and into MHR and as a result, MHR became a wholly-owned subsidiary
of Cimarex. On June 13, 2005, MHR merged with and into Cimarex, with Cimarex
being the surviving company and assuming all of the obligations of MHR under the
notes. The offer to acquire the 9.60% Notes (the 9.60% Notes Offer) and the
offer to acquire the Convertible Notes (the Convertible Notes Offer) are each
being made to satisfy Cimarex's contractual obligations under the indentures
governing the notes to offer to repurchase the notes in connection with the
mergers.

    The offers are scheduled to expire at 5:00 p.m., New York City time, on
August 5, 2005, unless extended.

    The 9.60% Notes Offer is to acquire any and all of the $195 million
outstanding principal amount of the 9.60% Notes at a repurchase price equal to
101% of the principal amount of the 9.60% Notes, plus accrued but unpaid
interest, up to and including the third business day after the expiration date
of the 9.60% Notes Offer. Holders may withdraw their tender from the 9.60% Notes
Offer at any time prior to the withdrawal time for the 9.60% Notes Offer, which
is midnight, New York City time, on August 8, 2005, unless extended. Specific
details of the 9.60% Notes Offer are fully described in the Change of Control
Notice and Offer to Purchase, dated July 6, 2005, relating to the 9.60% Notes
Offer.

    The Convertible Notes Offer is to acquire any and all of the $125 million
outstanding principal amount of the Convertible Notes at a repurchase price
equal to 100% of the principal amount of the Convertible Notes, plus accrued but
unpaid interest (including liquidated damages, if any, payable under the
Registration Rights Agreement entered into in connection with the original
offering of the Convertible Notes), up to, but not including, the expiration
date of the Convertible Notes Offer. Cimarex does not believe that any
liquidated damages have accrued, and does not expect any liquidated damages to
be payable in connection with the Convertible Notes Offer. Holders may withdraw
their tender from the Convertible Notes Offer at any time at or prior to the
expiration time of the Convertible Notes Offer, but not thereafter. Specific
details of the Convertible Notes Offer are fully described in the Change in
Control Notice and Offer to Purchase, dated July 6, 2005, relating to the
Convertible Notes Offer.

    Deutsche Bank Trust Company Americas is the depositary and the information
agent for the offers. Requests for assistance or documentation should be
directed to the information agent at c/o DB Services Tennessee, Inc., 648
Grassmere Park Road, Nashville, TN 37211, Attn: Reorganization Unit, telephone
(800) 735-7777. Beneficial owners of notes may also contact their brokers,
dealers, commercial banks, trust companies or other nominee through which they
hold their notes with questions and requests for assistance.

    This press release is neither an offer to purchase nor a solicitation of an
offer to sell securities. The 9.60% Notes Offer is being made solely by the
Change of Control Notice and Offer to Purchase for the 9.60% Notes Offer and the
related Letter of Transmittal, and the Convertible Notes Offer is being made
solely by the Change in Control Notice and Offer to Purchase for the Convertible
Notes and the related Letter of Transmittal, which are being mailed to
noteholders today. Additional copies of these documents and the other offer
materials may be obtained by contacting the information agent.



    About Cimarex Energy
    Denver-based Cimarex Energy Co. is an independent oil and gas exploration
and production company with principal operations in the Mid-Continent, Gulf
Coast, Permian Basin of West Texas and New Mexico and Gulf of Mexico areas of
the U.S.

    Important Additional Information Concerning The Convertible Notes Offer Will
Be Filed With The SEC.

    Cimarex plans to file today with the SEC a Schedule TO in connection with
the Convertible Notes Offer. The Schedule TO, including the related Change in
Control Notice and Offer to Purchase for the Convertible Notes and Letter of
Transmittal, will contain important information about Cimarex, the Convertible
Notes, the Convertible Notes Offer and related matters. Investors and security
holders are urged to read the Schedule TO carefully when it becomes available. A
copy of the Schedule TO, excluding the exhibits thereto, is attached to the
Change in Control Notice and Offer to Purchase for the Convertible Notes that is
being mailed to noteholders today.

    Investors and security holders may obtain free copies of the Schedule TO and
other documents filed with the SEC by Cimarex through the web site maintained by
the SEC at www.sec.gov. In addition, investors and security holders may obtain
free copies of the Schedule TO from Cimarex by written or oral request, Attn:
Corporate Secretary, 1700 Lincoln Street, Suite 1800, Denver, Colorado
80203-4518, telephone (303) 295-3995.

CONTACT:  Mark Burford, Director of Capital Markets of Cimarex Energy
Co., +1-303-295-3995