Data on 1800 term babies, 600 from each of the Chinese, Malay and Indian racial groups, were used to identify the factors affecting birthweight in Singapore. After adjustment for gestation, maternal height and other variables, the mean Indian birthweight was 100 g less than for the Chinese (P less than 0.001), 0.001), while the Malays averaged 33 g less than the Chinese. The shortfall in Indian birthweight is thought to be due, at least partly, to environmental factors.