Pioneer Southwest Energy Partners L.P. (“Pioneer Southwest”)
(NYSE:PSE) today announced a cash distribution of $0.50 per unit
on Pioneer Southwest's outstanding common units for the quarter ended
March 31, 2009. The distribution is payable May 14, 2009, to unitholders
of record at the close of business on May 7, 2009.
Pioneer Southwest is a Delaware limited partnership with headquarters in
Dallas and formed by Pioneer Natural Resources Company to own and
acquire oil and gas assets in its area of operations. This area includes
onshore Texas and eight counties in the southeast region of New Mexico.

Pioneer Southwest Energy Partners L.P.
Investors:
Frank
Hopkins, 972-969-4065
or
Nolan Badders, 972-969-3955
or
Media
and Public Affairs:
Susan Spratlen, 972-969-4018