To examine genetic affinity among Oceanian Populations. polymorphisms of exons six and seven of the ABO blood group gene (ABO) were Investigated in three populations-Munda town. Paradise village, and Rawaki villaae-in the New Georgia group of the Solomon Islands. The Munda and Paradise populations consist of Austronesian (AN)-spcaking Melanesians; the Rawaki Population consists of AN-speaking Micronesians who migrated from the Gilbert Islands to the New Georgia Islands approximately 30 years ago. We recently described the polymorphisms of ABO in three other Oceanian populations-Balopa Islanders (AN-speaking Melanesians), Gidra (non-AN-speaking Melanesians), and Tongans (AN-speaking Polynesians). The results from these six Oceanian Populations suggest: (1) the main alleles in Oceanian populations are ABO*A101, ABO*A102, ABO*B101, ABO*001, and ABO*002, among which the most predominant is ABO*001, and (2) there are marked differences in the ABO allele frequency spectrum among Oceanian Populations. The different geographical distribution of ABO alleles provides insight into the migration history of AN-speaking populations in Oceania.