Polymorphism of caprine milk proteins was studied by capillary electrophoresis. Identification of casein (CN) fractions was effected by using isolated fractions from cation-exchange fast protein liquid chromatography. Genetic polymorphisms in caprine alpha s2-CN, alpha s1-CN, beta-CN and kappa-CN have been determined. kappa-CN A and B, beta-CN A and null, alpha s2-CN A, B and C, alpha s1-CN A, B, C and null, and other forms with intermediate and low alpha s1-CN content have been identified. The capillary electrophoresis method made it possible to analyse whole caprine milk using simple sample preparation and was rapid, automated and suitable for phenotyping studies. This method may also permit the quantitative study of different protein fractions.