Previous studies have shown that serum concentrations of lipoprotein(a) [Lp(a)] are markedly different among different ethnic groups. We examined the serum levels of total cholesterol, high density lipoprotein (HDL) cholesterol and Lp(a) in apparently healthy subjects aged 20-69 years in Japan (n = 865) and the Dominican Republic (n = 1,893). Dominicans had significantly lower levels of total cholesterol and HDL cholesterol than Japanese. The distribution of Lp(a) concentrations were markedly skewed towards low levels in both Japanese and Dominicans. However, the mean Lp(a) concentration in Dominicans was approximately 2 times higher than in Japanese (21.7 +/- 23.7 vs 12.3 +/- 15.9 mg/dl, p < 0.001). This is possibly because the majority of Dominicans are of mixed Negroid and European blood.