Poly[(vinyl alcohol)-co-(vinyl amine)] was prepared by copolymerization of vinyl acetate and N-vinyl forma-mide, followed by a two-step alkaline hydrolysis in which the vinyl acetate groups were hydrolyzed to vinyl alcohol groups, and the N-vinyl formamide groups, to amino groups. This copolymer was used as the stabilizer for the emulsion polymerization of styrene using persul-fate-ion initiator. The latexes were cationic; the particles were relatively uniform and of 100–500 nm diameter. The presence of amino groups was shown by electro-phoresis and Kjeldahl analysis. Comparison with sodium lauryl sulfate showed that the mechanism of particle nucleation was apparently entry of radicals into fine emulsion droplets rather than the conventional entry of radicals into emulsifier micelles.