Duncan Energy Partners Announces Sale of 943,400 Additional Common Units

HOUSTON--(Business Wire)--
Duncan Energy Partners L.P. (NYSE:DEP) announced today that the underwriters of
its recent common unit offering have exercised their option to purchase an
additional 943,400 common units as part of DEP`s common unit offering that was
priced on June 15, 2009 at a public offering price of $16.00 per common unit.

The net proceeds from the sale of the 943,400 additional common units will be
approximately $14.5 million after deducting underwriting discounts and
commissions. DEP intends to use these net proceeds to repurchase an equal number
of its common units owned by an affiliate of Enterprise Products Partners L.P.
at the same net price per unit, after deducting underwriting discounts and
commissions.

UBS Investment Bank, Barclays Capital, Citi, Morgan Stanley and Wells Fargo
Securities are joint book-running managers for the offering. An investor may
obtain a free copy of the prospectus as supplemented by visiting EDGAR on the
SEC website at www.sec.gov. A copy of the final prospectus supplement and
related base prospectus may also be obtained from the underwriters as follows:
UBS Investment Bank, Prospectus Dept., 299 Park Ave., New York, NY, 10171, or by
calling toll-free (888) 827-7275; Barclays Capital, c/o Broadridge, Integrated
Distribution Services, 1155 Long Island Ave., Edgewood, NY, 11717, or by calling
toll-free (888) 603-5847 or by email at barclaysprospectus@broadridge.com; Citi,
Brooklyn Army Terminal, Attention: Prospectus Dept., 140 58th Street, 8th floor,
Brooklyn, NY, 11220, by email at batprospectusdept@citi.com or by calling
toll-free (800) 831-9146; Morgan Stanley, Attention: Prospectus Dept., 180
Varick Street, 2nd floor, New York, NY, 10014, or by calling toll-free (866)
718-1649 or by email at prospectus@morganstanley.com; Wells Fargo Securities,
Attention: Equity Syndicate Dept., 375 Park Ave., New York, NY, 10152, or by
calling toll-free (800) 326-5897, or by email at equity.syndicate@wachovia.com.

This press release shall not constitute an offer to sell or the solicitation of
an offer to buy the units described herein, nor shall there be any sale of these
units in any state or jurisdiction in which such an offer, solicitation or sale
would be unlawful prior to registration or qualification under the securities
laws of any such jurisdiction. The offering is being made only by means of a
prospectus and related prospectus supplement meeting the requirements of Section
10 of the Securities and Exchange Act of 1933, which are part of an effective
registration statement.

Duncan Energy Partners is a publicly traded partnership that provides midstream
energy services, including gathering, transportation, marketing and storage of
natural gas, in addition to NGL fractionation (or separation), transportation
and storage and petrochemical transportation and storage. Duncan Energy Partners
owns interests in assets located primarily in Texas and Louisiana, including
interests in approximately 9,200 miles of natural gas pipelines with a
transportation capacity aggregating approximately 6.8 billion cubic feet ("Bcf")
per day; more than 1,600 miles of NGL and petrochemical pipelines featuring
access to the world`s largest fractionation complex at Mont Belvieu, Texas; two
NGL fractionation facilities located in south Texas; approximately 18 million
barrels ("MMBbls") of leased NGL storage capacity; 8.5 Bcf of leased natural gas
storage capacity; and 34 underground salt dome caverns with more than 100 MMBbls
of NGL storage capacity at Mont Belvieu. Duncan Energy Partners L.P. is managed
by its general partner, DEP Holdings, LLC, which is wholly-owned by a subsidiary
of Enterprise Products Partners L.P.

Duncan Energy Partners L.P.
Investor Relations
Randy Burkhalter, 713-381-6812
or
Media Relations
Rick Rainey, 713-381-3635

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