Abstract: Method of preparing pulverulent polymer or copolymer compositions based on vinyl chloride and suitable for immediate use comprising preparing a master mixture of said polymers and/or copolymers based on vinyl chloride and additives employed therewith in use by mixing in an aqueous medium one or more of said polymers and/or copolymers and said additives in the form of liquid additives and/or fusible solid additives, the liquid additives and at least part of the fusible solid additives being introduced with agitation in the form of one or more dispersions of finely divided particles of a homogeneous phase in water, and mixing the master mixture with the remainder of the polymer and/or copolymers based on vinyl chloride.