MarkWest Energy Partners, L.P. (NYSE: MWE) will announce fourth quarter and full year 2010 financial results after market close on Monday, February 28, 2011, and will host a conference call to discuss the results at 4:00 p.m. ET on Tuesday, March 1, 2011.

The conference call can be accessed by dialing (800) 475-0218 (passcode ?MarkWest?) or via webcast by accessing the ?Investor Relations? page of the MarkWest website at www.markwest.com.

A replay of the conference call will be accessible on the MarkWest website or by dialing (800) 879-1270 (no passcode required).

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 we believe that the expectations reflected in the forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect our operations, financial performance, and other factors as discussed in our 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 we file with the SEC, including our Annual Report on Form 10-K for the year ended December 31, 2009, and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2010. 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.? We do not undertake any duty to update any forward-looking statement except as required by law.

MarkWest Energy Partners, L.P.
Frank Semple, 866-858-0482
Chairman, President & CEO
or
Nancy Buese, 866-858-0482
Senior VP & CFO
or
Dan Campbell, 866-858-0482
VP of Finance & Treasurer
investorrelations@markwest.com