Seven Indian geographical populations of D. melanogaster and ten oriental Drosophila species were assayed electrophoretically for Adh genic variation. Except four Drosophila species, most species revealed monomorphism or occurrence of one most frequent (>96%) and one rare allele. The Indian geographical populations of D. melanogaster revealed significant clinal variation (3% for 10 latitude) at Adh locus and AdhF allelic frequency correlated significantly with increase in latitude. It was suggested that the abundance of secondary alcohols in the southern Indian tropical and humid environment might exert selective pressure favouring higher frequency of AdhS allele. Patterns of ethanol utilsation as well as ethanol tolerance were analysed in larval and adult individuals of seven geographical populations of D. melanogaster and three Drosophila species. The D. melanogaster populations revealed latitudinal variation in tolerance along north-south axis while other Drosophila species showed interspecific divergence of ethanol tolerance levels. The parrel occurrence of latitudinal variation of Adh locus as well as ethanol tolerance in Indian geographical populations of D. melanogaster could be maintained by balancing natural selection varying spatially along the north-south axis of the Indian sub-continent.