The molecular polymorphism displayed by apolipoprotein E (apoE, protein; APOE, gene) has been listed as a risk factor for susceptibility to various disorders, such as those associated with lipid metabolism and arteriosclerosis. Data from many population groups are available. The present study endeavors to add to the world population database for alleles encountered at this locus. One hundred sixty-five individuals representing four castes and a mixed group from Punjab, a state in northwestern India, were analyzed for APOE isotyping. Intercaste group comparisons of allele frequencies revealed statistically insignificant differences, pointing to homogeneity at this locus among Punjabi caste groups, which can be considered as one Punjabi population. A further comparison of this Punjabi sample with other populations of the world revealed the Punjabi population to be closer to some European populations than to either African or Asian populations, a pointer to the ethnic origins of the Punjabi population.