Cadmium concentrations in whole blood were measured in subjects with no occupational exposure to cadmium. The study covered 128 males and 150 females from the three main ethnic groups in Singapore (namely Chinese, Malays and Indians). The geometric means (GM) of blood cadmium (CdB) levels of non-smoking males and females were 0.21 microgram/l and 0.26 microgram/l, respectively. Smokers had higher GM CdB levels than non-smokers. Significant ethnic differences were observed in both sexes, with Indian males having the highest GM CdB level of 0.48 microgram/l. Among the females, the Chinese had the highest GM CdB level: 0.33 microgram/l. Differences in dietary habits may have contributed to the observed ethnic differences in blood cadmium levels.