The genetic distances between the American Indians and the three major races of man, Caucasoids, Negroids and Mongoloids, were determined by using gene frequency data on 14 blood group and 12 protein loci. The results support the general view that the ancestry of the American Indian is predominantly Mongoloid. Using 30,000 years as the separation time between the American Indian and Mongoloid, the divergence time between the three major races of man was estimated to be 33,000-92,000 years.