X0303 4 2010-06-02 0 0001364541 EAGLE ROCK ENERGY PARTNERS L P EROC 0001398355 MILLS JOSEPH A EAGLE ROCK ENERGY PARTNERS, L.P. P.O. BOX 2968 HOUSTON TX 77252 1 1 0 0 CEO and Chairman Subscription Rights 2.50 2010-06-02 4 F 0 21190 3.2527 D 2010-06-01 2010-06-30 Common Units and Warrants 21190 100405 D Each subscription right entitles the holder to acquire, for $2.50 in cash, (i) one common unit and (ii) one warrant to purchase an additional common unit for $6.00 on certain days starting on or about the close of the rights offering period through May 15, 2012. The reporting person surrendered 21,190 subscription rights to satisfy tax withholding liabilities upon distribution of subscription rights received on restricted units in accordance with Rule 16b-3. Includes subscription rights received on both restricted and unrestricted common units. The reporting person is Chief Executive Officer and Chairman of Eagle Rock Energy G&P, LLC the general partner of Eagle Rock Energy GP, L.P. the general partner of registrant. /s/ Charles C. Boettcher, Attorney-In-Fact 2010-06-04