The bimetallic ruthenium complex [(1,3,5-C6H3i-Pr3)Ru(m-Cl)3RuCl(C2H4)(PCy3)] has been synthesized by reaction of [(1,3,5-C6H3i-Pr3)RuCl2)]2 with one equivalent of PCy3 in the presence of ethylene. It can be used as a catalyst precursor for the controlled atom transfer radical polymerization of methacrylates at 35 °C. The resulting polymers show low polydispersities.