Abstract: The vinyl monomers, such as methacrylates, have been polymerized with hydrazine hydrate (HZH) as initiator. The rates of polymerization are various with the structure of monomer as well as the polarity of solvent. The overall energy and initiation energy of polymerization for system of MMA-EtOH have been estimated to be 9.05 and 8.31 kcal/mol respectively.From the relationship between the polymerization and oxygen absorption the tentative initiation mechanism has been proposed.