Rio Vista Energy Partners L.P., or “Rio Vista”, an energy master limited partnership, announced today that its indirect, wholly-owned subsidiaries, Rio Vista Penny LLC and Rio Vista GO LLC, have completed the acquisition of assets and/or equity including certain leasehold interests of oil and gas producing properties (the “Properties”) and associated pipeline gathering systems from three privately held companies (the “Sellers”) based in East Central Oklahoma which have geographically contiguous operations. The acquisitions are expected to be immediately accretive to Rio Vista’s 2007 financial results.

“The acquisition of these Properties establishes a significant reserve position for Rio Vista, and provides excellent prospective drilling candidates,” said Doug Manner, Chairman of the Board of Rio Vista GP. Ian Bothwell, Acting Chief Executive Officer added: “We have already identified immediate opportunities which will provide significant additional production, including workovers of certain wells and drilling of specific locations. The funding for these projects has already been arranged and we expect to begin immediately. I fully expect that once completed we will achieve immediate results. The Properties are located in areas known for generating prolific amounts of natural gas, which we expect will significantly enhance our revenue, cash flow and reported earnings. We believe that these Properties represent the initial step in transforming Rio Vista into a diversified oil and gas producer.”

Rio Vista’s subsidiaries paid approximately $29.0 million for the Properties, comprised of the assumption of senior secured debt of $16.8 million, payment of accrued interest of approximately $0.3 million, assumption of $0.5 million of third party obligations and payment of $11.4 million to the Sellers, paid as follows: the issuance of approximately $1.5 million of Rio Vista common units, the issuance of a short-term convertible note of $0.5 million and $9.4 million in cash.

Rio Vista Penny assumed the senior secured debt of one of the Sellers pursuant to a $30.0 million credit facility provided by TCW Asset Management Company (“TCW”) as agent. The amount of the initial draw under the facility was approximately $23.8 million, consisting of approximately $16.8 million in assumption of the existing indebtedness of one of the Sellers, $2 million in consideration for TCW to enter into the credit facility with Rio Vista Penny and for Rio Vista Penny to purchase an overriding royalty interest held by an affiliate of TCW, $3 million to fund the acquisition of equity interests by Rio Vista GO, and $2 million to fund an approved plan of development.

The Properties located in East-Central Oklahoma are situated in McIntosh, Haskell and Pittsburg Counties. The leases comprise approximately 22,000 gross HBP (held by production) acres, a 25-mile pipeline that gathers natural gas from several Properties located in Haskell and Pittsburg Counties and a 40-mile pipeline that receives natural gas from leases in the Texanna area north of Lake Eufaula and delivers to the ONG-R-900 intrastate pipeline in McIntosh County. The Companies collectively control a majority interest in a total of 93 operated wells and 16 non-operated wells primarily from Booch sand, Hartshorne Coal Bed Methane, George’s Fork and Spiro wells. One of the Companies is presently involved in the development of the shallow reserve targets. There are an additional 114 identified drilling locations in the upper formations with upside potential. Rio Vista’s subsidiaries intend to explore the additional upside opportunities that exist in the deeper formations located on the Properties such as the Caney Shale and Woodford Shale. Based on recently completed reserve reports, the Properties have estimated natural gas reserves of 9 BCF, made up of approximately 2.8 BCF proved developed reserves 6.2 BCF proved undeveloped reserves.