To determine the relationship between the nutritional status of the mother and that of the child, 339 children aged 3-36 months and their mothers in two urban hospitals and a community out-patient clinic, were studied. The weight and height of both children and their mothers were measured, and body mass indices (BMI) of the mothers were calculated. Socio-economic status, maternal educational level, and dietary information were recorded in a predesigned questionnaire. The child's nutritional status, as indicated by weight for age (as a percentage of NCHS median), was associated with the body mass index of the mother (P < 0.001), socio-economic status of the family (P < 0.001), and breastfeeding status of the child (P < 0.005) in a multivariate analysis after adjusting for several prognostic factors. The results indicate that maternal nutritional status is a proximate determinant of a child's nutritional status and should be considered in programmes aiming at improving child health.