Exhibit 11

MARKWEST HYDROCARBON, INC.

COMPUTATION OF EARNINGS PER COMMON SHARE

(in thousands, except per share data)

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2003		2002			2003		2002
	(in thousands, except per share data)
Net income (loss)	$	9,979	$	(2,075	)	$	8,937	$	(1,898	)
Weighted average number of outstanding shares of common stock	9,351		9,369			9,356		9,356
Basic earnings (loss) per share	$	1.07	$	(0.22	)	$	0.96	$	(0.20	)
Net income (loss)	9,979		(2,075		)	8,937		$	(1,898	)
Weighted average number of outstanding shares of common stock	$	9,351	$	9,369		$	9,356	9,356
Dilutive stock options	20		33			20		25
Earnings (loss) per share assuming dilution	$	1.06	$	(0.22	)	$	0.95	$	(0.20	)