An approach to branched vinyl polymers through radical polymerization in the presence of 3-mercaptohexyl methacrylate (MHM) as the chain transfer monomer is reported in this paper. In the case of polymerization at styrene(100)-MHM5.0-AIBN(2.0), the molecular weight increased with conversion and reached a value of >7.3 x 10(5) g/mol at 99% conversion; in addition, the Zimm branching factor, g', was less than 1 and decreased with conversion, when the formation of the branched chain and development of branching was supposed. The bridging units in the obtained polymer, generating from MHM, were cleaved to yield the primary chains. These results have confirmed the formation of branched polymers. Moreover, this study successful prepared branched poly(methyl methacrylate) and poly(vinyl acetate). This methodology proposes good prospects for scaling-up and thereby offers a wide range of branched vinyl polymers at low cost.