Plasma uric acid was investigated in a population survey on diabetes and cardiovascular risk factors among Melanesians and Asian Indians in Fiji in 1980. Plasma uric acid levels were elevated in men and women with impaired glucose tolerance in both ethnic groups. The lowest plasma uric acid levels were found in diabetic patients, especially in diabetic men. Even though obesity was positively associated with plasma uric acid, it did not explain the high plasma uric acid level in persons with impaired glucose tolerance. Body mass index had a significant and independent impact on plasma uric acid levels both in nondiabetic and diabetic men and women. The strongest predictor of plasma uric acid in the multiple regression analysis in our study populations was plasma creatinine: it alone explained 9% of the variation in men and 2% in women; and 24% in Melanesians and 5% in Asian Indians. Our findings suggest a strong renal involvement in the balance of plasma uric acid and may also reflect certain dietary patterns, such as a high intake of protein, fats, and certain local vegetables. Although the prevalence of hyperuricemia was high, 27% in both Melanesian men and women, 22% in Asian Indian men, and 11% in Asian Indian women, clinical gout was uncommon. Many predictor variables and their interactions were analyzed along with the reasons for the high plasma uric acid levels in persons with impaired glucose tolerance and for the low plasma uric acid levels in diabetic patients.