The aim of this study was to determine the effect of maternal nutrition, vitamin supplementation and socioeconomic status on infants birth weight in Kuwait. The weight of 1995 newborn Kuwaiti infants was recorded shortly after delivery. Data on mothers' bodyweight just before pregnancy, height, weight gain during pregnancy and vitamin intake were recorded. Mothers were interviewed to collect data in family income, educational level and employment during pregnancy. The results show that mean birth weight in Kuwait (3.50 Kg) compares favourably with any country. The birth weight was affected by several factors. Maternal body weight, height and weight gain during pregnancy were positively correlated with birth weight. The results also show that the intake of vitamin supplement during pregnancy did not have a significant inference on birth weight. Obese mothers consuming a reducing diet delivered babies with birth weight slightly above normal. The results show that mothers from high income families had heavier babies when compared with a low income group. On the other hand, educated and employed mothers were more liable to have slightly smaller babies when compared with illiterate or unemployed mothers.