Variations in allelle frequencies at 11 serological and biochemical loci among 21 endogamous Dhangar castes of Maharashtra, India, have been studied using Wright's FST statistic. Gene differentiation among these castes is only about 4 per cent at these polymorphic loci. The distributional form of FST is explicable by random genetic drift at this early stage of differentiation of these caste groups. The empirical relationship between the average allele frequencies and the ration of within to total gene diversity of the caste groups is also studied.