The frequencies of DPA1 and DPB1 alleles and their occurrence in haplotypic linkage were assessed and compared in Nigerian, Liberian, and Gabonese individuals. Differences were seen in the distribution patterns; these differences were more pronounced between the Gabonese and the other two populations than between Liberians and Nigerians. Several haplotypic DPA1-DPB1 combinations could be verified by homozygosity. Linkage disequilibria of DPA1-DPB1 combinations, indicating further probable haplotypes, were estimated. Although different allele and haplotype frequencies were recognized in the three subgroups, the linkage disequilibria were mostly either positive or negative in all populations.