This document specifies two methods for the determination of the chlorine content of homopolymers and copolymers of vinyl chloride, free from plasticizers or additives, namely: — method A (combustion in a bomb); — method B (combustion in a flask). This document is also applicable as a reference method for the determination of chlorine content in other chlorine-containing polymers(such as chlorinated polyvinyl chloride, polyvinyl chloride, chlorinated polyethylene and Vinyl chloride-vinyl acetate) without plasticizers and additives.