Five hundred fifteen samples from five populations of India (Brahmins, Marathas, Patels, and Parsees of western India and Hindus of Andhra Pradesh) were analyzed for transferrin subtypes using the isoelectric focusing technique. The allele frequencies of 8444 samples belonging to 93 populations of India have been tabulated, and data were analyzed for genetic diversity among geographic, regional, and socio-cultural groups. Three relatively common alleles, TF*C1, TF*C2, and TF*C3, showed wide variation in various populations of India. Compared with western India, a high frequency of the TF*C2 allele was observed in eastern India. This variation of the TF*C2 allele showed a geographic cline increasing from west to east, giving a significant positive correlation between the TF*C2 allele frequency and longitude. Various genetic processes that possibly maintain TF polymorphism are selection, admixture, genetic drift, and isolation by distance. The possible influence of various genetic processes is discussed.