A cross-sectional interpopulation analysis of blood pressure and its determinants was conducted with the data collected during epidemiologic surveys in 11 Pacific island populations from 1975 to 1981. In each of these populations, the mean arterial blood pressure increased with age; the overall blood pressure levels differed among the populations. The multivariate analyses suggest that dietary factors that result in differences in body mass, plasma cholesterol, and glucose intolerance contribute considerably to interpopulation differences in blood pressure. The impact of these differences in effects of dietary factors on interpopulation blood pressure seemed to be uniform, even though the overall levels of each of these three variables differed significantly among the populations. This study of blood pressure data, accrued from 6224 men and 7029 women aged 20-79 years, supports the hypothesis that dietary factors strongly contribute to high blood pressure as well as to interpopulation differences in the prevalence of hypertension. We propose using these data in planning programs for prevention and control of hypertension in the Pacific countries.