An early transition metal metallocene compound, Cp2ZrCl2, with an anionic surfactant, sodium n-dodecyl sulfate (SDS) as emulsifier has been found to be an effective catalyst for polymerization of monomers like styrene and methylmethacrylate in aqueous medium. The molecular weights of the polymers have been found to be very high with low molecular weight distribution. The added surfactant has been found to play the dual role of stabilizer of the cation as well as an emulsifying agent for the monomer. (c) 2005 Wiley Periodicals, Inc.