Ethene-propene copolymerizations were performed in the presence of C. symmetric group 4 metallocenes. The reactivity ratios were strongly influenced by both the transition metal and the ancillary ligands. Substantially alternate, almost random, and blocky copolymers were obtained with titanocene, zirconocene, and haffnocene, respectively, with the bis(dimethylsilyl)-1,1'-2,2'-diyl-(3',5'-diisopropyl)(4-isopropyl)(cyclopentadienyl) ligand, and a blocky copolymer was obtained with (diphenyl methylidene)(cyclopentadienyl)(9-fluorenyl)TiCl2.