exv99wa

JOINT FILING AGREEMENT

The undersigned each agree that (i) the statement on Schedule 13D relating to the common units representing limited partnership interests of Eagle Rock Energy Partners, L.P., a Delaware limited partnership, has been adopted and filed on behalf of each of them, (ii) all future amendments to such statement on Schedule 13D will, unless written notice to the contrary is delivered as described below, be jointly filed on behalf of each of them, and (iii) the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934 apply to each of them. This agreement may be terminated with respect to the obligation to jointly file future amendments to such statement on Schedule 13D as to any of the undersigned upon such person giving written notice thereof to each of the other persons signatory hereto, at the principal office thereof.

Dated: February 15, 2011


	EAGLE ROCK HOLDINGS, L.P. By its general partner, Eagle Rock GP, L.L.C.

	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Manager

	EAGLE ROCK GP, L.L.C.
	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Manager


	MONTIERRA MINERALS & PRODUCTION, L.P. By its general partner, Montierra Management LLC
	By:	/s/ Joseph A. Mills
		Joseph A. Mills
		Chief Executive Officer

	MONTIERRA MANAGEMENT LLC
	By:	/s/ Joseph A. Mills
		Joseph A. Mills
		Chief Executive Officer

	NATURAL GAS PARTNERS VII, L.P. By its general partner, G.F.W. Energy VII, L.P. By its general partner, GFW VII, L.L.C.
	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Authorized Member


	NATURAL GAS PARTNERS VIII, L.P. By its general partner, G.F.W. Energy VIII, L.P. By its general partner, GFW VIII, L.L.C.
	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Authorized Member

	NGP INCOME MANAGEMENT L.L.C.
	By:	/s/ Tony R. Weber
		Tony R. Weber
		President

	EAGLE ROCK HOLDINGS NGP 7, LLC By its sole member, Natural Gas Partners VII, L.P. By its general partner, G.F.W. Energy VII, L.P. By its general partner, GFW VII, L.L.C.
	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Authorized Member


	EAGLE ROCK HOLDINGS NGP 8, LLC By its sole member, Natural Gas Partners VIII, L.P. By its general partner, G.F.W. Energy VIII, L.P. By its general partner, GFW VIII, L.L.C.
	By:	/s/ Kenneth A. Hersh
		Kenneth A. Hersh
		Authorized Member



	/s/ Kenneth A. Hersh
	Kenneth A. Hersh