Endeavour Enters Into Agreement to Sell Cygnus Asset

Company reports continued US drilling success

HOUSTON, August 31, 2010 - Endeavour International Corporation (NYSE Amex: END) (LSE: ENDV) today
announced it has signed a definitive agreement to sell its Cygnus asset in
the Southern Gas Basin of the United Kingdom sector of the North Sea to
Bayerngas UK Ltd., the UK oil and gas subsidiary of Bayergas Norge AS, for a
cash consideration of US$110 million. The cash proceeds will not be burdened
by any current taxes payable. The transaction has been approved by the boards
of directors of both companies and is subject only to certain government and
joint venture partner approvals. Closing is expected to be completed within
60 days.

"The sale of our Cygnus asset and the recent completion of the financing
transaction places Endeavour in a fully funded position to execute our North
Sea and United States opportunities and achieve near-term production and cash
flow growth," said William L. Transier, chairman, chief executive officer and
president. "Our successful US initiative has already increased current daily
production for the company to nearly 6,000 barrels of oil equivalent per day
with approximately half from the US."

The company will use the proceeds from this sale and the recently
completed financing transaction to focus on its Rochelle and Bacchus
development projects in the UK North Sea and onshore Haynesville shale gas
play in the US. A well at West Rochelle, in the block adjacent to Rochelle,
is scheduled to spud in the next week and represents an opportunity to double
the size of the Rochelle development.

"The Cygnus transaction brings to close the strategic review process
regarding our North Sea assets and exemplifies the underlying value of our
remaining portfolio in the UK and our long-term ability to build value for
our investors," said Transier. "This sale allows us to reallocate resources
to nearer term growth projects and take execution risk out of our business
model."

Endeavour was advised during the strategic review process by Jefferies
International Limited and Lambert Energy Advisory Ltd.

Endeavour also announced results of its latest well in the Haynesville
play of Louisiana. The Woodard 10-1H horizontal well located in the
Woodardville Field in Red River Parish, Louisiana, flowed at an initial rate
of 22.6 million cubic feet per day (mmcfd) from a 24/64 choke at a flowing
pressure of 8,053 pounds per square inch. This represents the third
successive well in the Woodardville area to flow at these high rates.
Endeavour holds a 41.54 percent working interest in the well.

Endeavour International Corporation is an oil and gas exploration and
production company focused on the acquisition, exploration and development of
oil and natural gas in the North Sea and the United States. For more
information, visit endeavourcorp.com.

Certain statements in this news release should be regarded as
"forward-looking" statements within the meaning of the securities laws. These
statements speak only of as of the date made. Such statements are subject to
assumptions, risk and uncertainty. Actual results or events may vary
materially.

Investor Relations, Mike Kirksey of Endeavour, +1-713-307-8788; or UK Media, Philip Dennis, +44-0-20-7337-1516, or Henry Lerwill, +44-0-20-7337-1526, both of Pelham Bell Pottinger for Endeavour