Allozyme polymorphism for nine gene-enzyme systems were studied through horizontal starch gel electrophoresis in isofemale lines derived from six Indian populations of D. busckii. Five autosomal loci coded for dimeric Aph, Odh, Mdh, Me and Ao phenotypes, and allelic variants were represented by segregating single-band variants. complex Acph patterns were controlled by a duplicate locus while polymorphic esterase loci coded for monomeric enzymes. However, Adh and α-Gpdh were controlled by a single locus each and homozygous strain depicted epigenetic two-banded phenotypes. The Indian geographical populations of D.busckii revealed allozymic similarity at all the loci examined. However, the extent of genic diversity was found to be significantly higher than those of U.S. populations. The available data on the patterns of genetic structure of Indian as well as U.S. populations of D. busckii concurred with that of D.simulans in respect of allozymic homogeneity. lack of geographical clinal variation and lack of adaptive flexibility to a range of climatic conditions. Thus, the allozymic uniformity observed in D. busckii might constitute a genetic strategy for this colonising species in respect of its limited niche-width for spatial climatic adaptations.