The allele frequencies have been analyzed at one Short tandem repeat (STR) locus, 3' to the phosphoglycerate kinase (PGK) gene located within Xq11–Xq13 among four anthropologically distinct ethnic groups of South India namely Ezhavas, Nairs, Arayas and Muslims. Muslims are religio-ethnic group while other populations mentioned above belong to distinct section of Hindu religion. All these populations are from Kollam district of Kerala in South India and speak Malayalam, an Indo-Dravidian language. A total of 174 random, healthy individuals for PGK microsatellite were analyzed.