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  <p style="border:none;margin:0in 0in .0001pt;padding:0in;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  </div>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.1pt;">UNITED STATES</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.1pt;">SECURITIES AND EXCHANGE
  COMMISSION</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">Washington, D.C. 20549</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.1pt;">FORM&nbsp;8-K</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;letter-spacing:-.1pt;">CURRENT REPORT</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;letter-spacing:-.1pt;">PURSUANT TO SECTION&nbsp;13
  OR 15(d)&nbsp;OF</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;letter-spacing:-.1pt;">THE SECURITIES
  EXCHANGE ACT OF 1934</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">Date of Report (Date of earliest
  event reported): May&nbsp;12, 2008</font></b></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;letter-spacing:-.1pt;">MARKWEST
  ENERGY PARTNERS, L.P.</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Exact name of registrant as specified in its
  charter)</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
  
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    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">Delaware</font></b></p>
    </td>
    <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;letter-spacing:-.1pt;">&nbsp;</font></b></p>
    </td>
    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">001-31239</font></b><font size="2" style="font-size:10.0pt;"> </font></p>
    </td>
    <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;letter-spacing:-.1pt;">&nbsp;</font></b></p>
    </td>
    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">27-0005456</font></b></p>
    </td>
   </tr>
   <tr>
    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(State or other jurisdiction of<br>
    incorporation or organization)</font></p>
    </td>
    <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;letter-spacing:-.1pt;">&nbsp;</font></b></p>
    </td>
    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Commission File Number)</font></p>
    </td>
    <td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.0%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;letter-spacing:-.1pt;">&nbsp;</font></b></p>
    </td>
    <td width="32%" valign="top" style="padding:0in 0in 0in 0in;width:32.0%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(I.R.S. Employer<br>
    Identification Number)</font></p>
    </td>
   </tr>
  </table>
  
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  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">1515 Arapahoe Street, Tower 2, Suite&nbsp;700,
  Denver CO 80202</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Address of principal executive offices)</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Registrant&#146;s telephone number, including area
  code: <b>303-925-9200</b></font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">Not Applicable.</font></b></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Former name or former address, if changed since
  last report.)</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Check the appropriate box below if the Form&nbsp;8-K
  filing is intended to simultaneously satisfy the filing obligation of the
  registrant under any of the following provisions (see General Instruction A.2.
  below):</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt .25in;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;letter-spacing:-.1pt;">o</font><font size="2" style="font-size:10.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160; Written Communications pursuant
  to Rule&nbsp;425 under the Securities Act (17 CFR 230.425)</font></p>
  
  <p style="margin:0in 0in .0001pt .25in;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;letter-spacing:-.1pt;">o</font><font size="2" style="font-size:10.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160; Soliciting material pursuant to
  Rule&nbsp;14a-12 under the Exchange Act (17 CFR 240.14a-12)</font></p>
  
  <p style="margin:0in 0in .0001pt .5in;text-autospace:none;text-indent:-.25in;"><font size="2" face="Wingdings" style="font-size:10.0pt;letter-spacing:-.1pt;">o</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;letter-spacing:-.1pt;">Pre-Commencement communications
  pursuant to Rule&nbsp;14d-2(b)&nbsp;under the Exchange Act (17 CFR
  240.14d-2(b))</font></p>
  
  <p style="margin:0in 0in .0001pt .5in;text-autospace:none;text-indent:-.25in;"><font size="2" face="Wingdings" style="font-size:10.0pt;letter-spacing:-.1pt;">o</font><font size="1" style="font-size:3.0pt;letter-spacing:-.1pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;letter-spacing:-.1pt;">Pre-Commencement communications
  pursuant to Rule&nbsp;13e-4(c)&nbsp;under the Exchange Act (17 CFR
  240.13e-4(c))</font></p>
  
  <div style="border:none;border-bottom:double windowtext 6.0pt;padding:0in 0in 0in 0in;">
  
  <p style="border:none;margin:0in 0in .0001pt;padding:0in;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  </div>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <div style="margin:0in 0in .0001pt;text-autospace:none;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
  
  </div>
  <!-- SEQ.=1,FOLIO='',FILE='C:\JMS\c900118\08-11574-2\task2936187\11574-2-ba.htm',USER='c900118',CD='May 13 14:40 2008' -->
  
  
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  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">ITEM 2.02. Results of Operations and Financial Condition</font></b></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">On May&nbsp;12, 2008, MarkWest Energy Partners, L.P. (the &#147;Partnership&#148;) announced its consolidated financial results for the three months ended March&nbsp;31, 2008.&#160; A copy of the Partnership&#146;s earnings release is furnished as Exhibit&nbsp;99.1 to this Current Report on Form&nbsp;8-K.</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">&nbsp;</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">This information shall not be deemed &#147;filed&#148; for purposes of Section&nbsp;18 of the Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">&nbsp;</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">The earnings release furnished with this Current Report on Form&nbsp;8-K includes a presentation of the Partnership&#146;s distributable cash flow. Distributable cash flow is a financial measure that is not calculated in accordance with generally accepted accounting principles (&#147;GAAP&#148;). With the exception of maintenance capital expenditures, the amounts included in the calculation of distributable cash flow are computed in accordance with GAAP. Maintenance capital expenditures include only those capital expenditures that do not increase the capacity of an asset or generate additional revenues or cash flows from operations. A reconciliation of distributable cash flow to both income before provision for income tax and to net cash flows provided by operating activities, our most directly comparable GAAP financial measures, is provided in the earnings release.</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">&nbsp;</font></p><p style="color:#000033;margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" color="black" face="Times New Roman" style="color:windowtext;font-size:10.0pt;">We believe that investors benefit from having access to the same financial measures being utilized by management. Distributable cash flow is a significant metric used by our management to compare cash flows generated by the Partnership to the cash distributions we make to our common unitholders. Using this metric, management can compute the coverage ratio of these cash flows to cash distributions. This is an important financial measure for our limited partners (including common unitholders) because it is an indicator of our success in providing a cash return on their investment. Specifically, this financial measure shows investors whether or not the Partnership is generating cash flows at a level that can sustain or support an increase in our quarterly cash distributions paid to partners. Lastly, distributable cash flow is the quantitative standard used throughout the investment community with respect to publicly traded master limited partnerships.</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:ideograph-numeric;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">ITEM 9.01.&#160; Financial
  Statements and Exhibits.</font></b></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt 54.75pt;text-autospace:ideograph-numeric ideograph-other;text-indent:-18.75pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(d)</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Exhibits.</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
   <tr>
    <td width="7%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:7.88%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;No.</font></b></p>
    </td>
    <td width="7%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:7.96%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
    </td>
    <td width="84%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:84.16%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description of Exhibit</font></b></p>
    </td>
   </tr>
   <tr>
    <td width="7%" valign="top" style="border:none;padding:0in .7pt 0in .7pt;width:7.88%;">
    <h1 align="left" style="font-weight:bold;margin:0in 0in .0001pt;page-break-after:avoid;text-align:left;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:normal;">99.1</font></b></h1>
    </td>
    <td width="7%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:7.96%;">
    <h1 align="left" style="font-weight:bold;margin:0in 0in .0001pt;page-break-after:avoid;text-align:left;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:normal;">&nbsp;</font></b></h1>
    </td>
    <td width="84%" valign="top" style="border:none;padding:0in .7pt 0in .7pt;width:84.16%;">
    <h1 align="left" style="font-size:10.0pt;font-weight:bold;margin:0in 0in .0001pt;page-break-after:avoid;text-align:left;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:normal;">Press release dated May&nbsp;12, 2008, announcing
    first quarter 2008 financial results</font></b><font face="Times New Roman">.</font></h1>
    </td>
   </tr>
  </table>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2</font></p>
  
  <div style="margin:0in 0in .0001pt;text-autospace:none;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
  
  </div>
  <!-- SEQ.=1,FOLIO='2',FILE='C:\JMS\c900118\08-11574-2\task2936187\11574-2-ba.htm',USER='c900118',CD='May 13 14:40 2008' -->
  
  
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  <div>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;letter-spacing:-.1pt;">SIGNATURE</font></b></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Pursuant
  to the requirements of the Securities and Exchange Act of 1934, the Registrant
  has duly caused this report to be signed on its behalf by the undersigned,
  thereunto duly authorized.</font></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
  
  <table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="47%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:47.78%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">MARKWEST ENERGY PARTNERS, L.P.</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">(Registrant)</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">By:</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">MarkWest Energy GP, L.L.C.,</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Its General Partner</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Date: May&nbsp;13, 2008</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">By:</font></p>
    </td>
    <td width="43%" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">/s/ NANCY K. BUESE</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;letter-spacing:-.1pt;">&nbsp;</font></p>
    </td>
    <td width="43%" valign="top" style="border:none;padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;letter-spacing:-.1pt;">Nancy K. Buese</font></p>
    </td>
   </tr>
   <tr>
    <td width="52%" valign="top" style="padding:0in .7pt 0in .7pt;width:52.22%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><i><font size="2" face="Times New Roman" style="font-size:1.0pt;font-style:italic;letter-spacing:-.1pt;">&nbsp;</font></i></p>
    </td>
    <td width="4%" valign="top" style="padding:0in .7pt 0in .7pt;width:4.44%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><i><font size="2" face="Times New Roman" style="font-size:1.0pt;font-style:italic;letter-spacing:-.1pt;">&nbsp;</font></i></p>
    </td>
    <td width="43%" valign="top" style="padding:0in .7pt 0in .7pt;width:43.34%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><i><font size="2" face="Times New Roman" style="font-size:10.0pt;font-style:italic;letter-spacing:-.1pt;">Senior Vice President and
    Chief Financial Officer</font></i></p>
    </td>
   </tr>
  </table>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3</font></p>
  
  <div style="margin:0in 0in .0001pt;text-autospace:none;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
  
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  <div style="font-family:Times New Roman;">
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">EXHIBIT
  INDEX</font></b></p>
  
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
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    <td width="6%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:6.2%;">
    <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit<br>
    Number</font></b></p>
    </td>
    <td width="6%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:6.12%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
    </td>
    <td width="87%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:87.68%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;Title</font></b></p>
    </td>
   </tr>
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    <td width="6%" valign="top" style="border:none;padding:0in .7pt 0in .7pt;width:6.2%;">
    <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:ideograph-numeric ideograph-other;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">99.1</font></p>
    </td>
    <td width="6%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:6.12%;">
    <p style="margin:0in 0in .0001pt;text-autospace:ideograph-numeric ideograph-other;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
    </td>
    <td width="87%" valign="top" style="border:none;padding:0in .7pt 0in .7pt;width:87.68%;">
    <p style="margin:0in 0in .0001pt;text-autospace:ideograph-numeric ideograph-other;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Press release dated May&nbsp;12, 2008,
    announcing first quarter 2008 financial results</font><font size="2" style="font-size:10.0pt;">.</font></p>
    </td>
   </tr>
  </table>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4</font></p>
  
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text: UNITED STATES
  SECURITIES AND EXCHANGE
  COMMISSION
  Washington, D.C. 20549
  FORM 8-K
  CURRENT REPORT
  PURSUANT TO SECTION 13
  OR 15(d) OF
  THE SECURITIES
  EXCHANGE ACT OF 1934
  Date of Report (Date of earliest
  event reported): May 12, 2008
  MARKWEST
  ENERGY PARTNERS, L.P.
  (Exact name of registrant as specified in its
  charter)
  Delaware
  001-31239
  27-0005456
  (State or other jurisdiction of
  incorporation or organization)
  (Commission File Number)
  (I.R.S. Employer
  Identification Number)
  1515 Arapahoe Street, Tower 2, Suite 700,
  Denver CO 80202
  (Address of principal executive offices)
  Registrant's telephone number, including area
  code:
  303-925-9200
  Not Applicable.
  (Former name or former address, if changed since
  last report.)
  Check the appropriate box below if the Form 8-K
  filing is intended to simultaneously satisfy the filing obligation of the
  registrant under any of the following provisions (see General Instruction A.2.
  below):
  o
  Written Communications pursuant
  to Rule 425 under the Securities Act (17 CFR 230.425)
  o
  Soliciting material pursuant to
  Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
  o
  Pre-Commencement communications
  pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
  240.14d-2(b))
  o
  Pre-Commencement communications
  pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
  240.13e-4(c))
  ITEM 2.02. Results of Operations and Financial Condition
  On May 12, 2008, MarkWest Energy Partners, L.P. (the "Partnership") announced its consolidated financial results for the three months ended March 31, 2008.  A copy of the Partnership's earnings release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.
  This information shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.
  The earnings release furnished with this Current Report on Form 8-K includes a presentation of the Partnership's distributable cash flow. Distributable cash flow is a financial measure that is not calculated in accordance with generally accepted accounting principles ("GAAP"). With the exception of maintenance capital expenditures, the amounts included in the calculation of distributable cash flow are computed in accordance with GAAP. Maintenance capital expenditures include only those capital expenditures that do not increase the capacity of an asset or generate additional revenues or cash flows from operations. A reconciliation of distributable cash flow to both income before provision for income tax and to net cash flows provided by operating activities, our most directly comparable GAAP financial measures, is provided in the earnings release.
  We believe that investors benefit from having access to the same financial measures being utilized by management. Distributable cash flow is a significant metric used by our management to compare cash flows generated by the Partnership to the cash distributions we make to our common unitholders. Using this metric, management can compute the coverage ratio of these cash flows to cash distributions. This is an important financial measure for our limited partners (including common unitholders) because it is an indicator of our success in providing a cash return on their investment. Specifically, this financial measure shows investors whether or not the Partnership is generating cash flows at a level that can sustain or support an increase in our quarterly cash distributions paid to partners. Lastly, distributable cash flow is the quantitative standard used throughout the investment community with respect to publicly traded master limited partnerships.
  ITEM 9.01.  Financial
  Statements and Exhibits.
  (d)
  Exhibits.
  Exhibit No.
  Description of Exhibit
  99.1
  Press release dated May 12, 2008, announcing
    first quarter 2008 financial results
  .
  2
  SIGNATURE
  Pursuant
  to the requirements of the Securities and Exchange Act of 1934, the Registrant
  has duly caused this report to be signed on its behalf by the undersigned,
  thereunto duly authorized.
  MARKWEST ENERGY PARTNERS, L.P.
  (Registrant)
  By:
  MarkWest Energy GP, L.L.C.,
  Its General Partner
  Date: May 13, 2008
  By:
  /s/ NANCY K. BUESE
  Nancy K. Buese
  Senior Vice President and
    Chief Financial Officer
  3
  EXHIBIT
  INDEX
  Exhibit
  Number
  Exhibit Title
  99.1
  Press release dated May 12, 2008,
    announcing first quarter 2008 financial results
  .
  4