Abstract: This invention provides a new one step polymerization process suitable for preparing latex and paste resins of PVC polymer or its copolymers. At the beginning of polymerization, a small amount of water (less than 1 part per 4 parts by weight of monomer) having a water-soluble initiator dissolved in it is suspended in a large amount of vinyl chloride monomer and comonomer so as to initiate the reaction. As the reaction proceeds the remaining initiator solution and an emulsifier solution are added continuously or batchwise over an extended period. At the end of the polymerization, a stable latex is obtained having polymer particles about one micron or greater in diameter.