The present invention provides a process for the manufacture of vinyl chloride polymers by polymerization of the monomer or monomer mixture in aqueous dispersion in the presence of radical-forming catalysts and optionally suspension stabilizers, emulsifiers and further polymerization auxiliaries, which comprises carrying out the polymerization in a reactor the inner walls of which and other parts were polymer deposits may form are coated partially or entirely with a coating containing determined compounds of the formula In accordance with this invention, a substantial suppression of polymer deposit formation is achieved especially in the case of the vinyl chloride copolymers.