HLA antigen distributions in persons with normal and abnormal glucose tolerance were compared in four Pacific populations. The populations included Melanesians from the Fijian Islands, Loyalty Islands and mainland New Caledonia and Polynesians from the Wallis Islands. HLA-DR results are provided for the first time for Pacific groups. In Polynesians, HLA-B22 was increased in frequency in patients with non-insulin-dependent diabetes mellitus and also in persons with impaired glucose tolerance. However, the association was not statistically significant when corrected for the number of antigens tested. A similar increase in HLA-B22, although not significant, was seen in each of the three Melanesian populations with abnormal glucose tolerance. No other consistent increase in any HLA antigen occurred in persons with abnormal plasma glucose concentrations.