Exhibit 99.1

MarkWest Energy Partners Announces Quarterly Cash Distribution

DENVER—April 22, 2010— MarkWest Energy Partners, L.P. (NYSE: MWE) today announced that the Board of Directors of the General Partner of MarkWest Energy Partners, L.P., declared a cash distribution of $0.64 per common unit for the first quarter of 2010, for an implied annual rate of $2.56 per common unit.

The first quarter 2010 distribution is payable May 14, 2010, to unitholders of record on May 3, 2010.  The ex-dividend date is April 29, 2010.

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MarkWest Energy Partners, L.P. is a master limited partnership engaged in the gathering, transportation, and processing of natural gas; the transportation, fractionation, marketing, and storage of natural gas liquids; and the gathering and transportation of crude oil. MarkWest has extensive natural gas gathering, processing, and transmission operations in the southwest, Gulf Coast, and northeast regions of the United States, including the Marcellus Shale, and is the largest natural gas processor in the Appalachian region.

This press release includes “forward-looking statements.”  All statements other than statements of historical facts included or incorporated herein may constitute forward-looking statements.  Actual results could vary significantly from those expressed or implied in such statements and are subject to a number of risks and uncertainties.  Although MarkWest believes that the expectations reflected in the forward-looking statements are reasonable, MarkWest can give no assurance that such expectations will prove to be correct.  The forward-looking statements involve risks and uncertainties that affect operations, financial performance, and other factors as discussed in filings with the Securities and Exchange Commission.  Among the factors that could cause results to differ materially are those risks discussed in the periodic reports filed with the SEC, including MarkWest’s Annual Report on Form 10-K for the year ended December 31, 2009.  You are urged to carefully review and consider the cautionary statements and other disclosures made in those filings, specifically those under the heading “Risk Factors.”  MarkWest does not undertake any duty to update any forward-looking statement except as required by law.