The results of a food supplementation study conducted in four chronically malnourished rural villages in Guatemala were analyzed to determine possible effects on the study children's early mental and physical development. One of two food supplements, atole and fresco, were given to pregnant and lactating mothers and the infants born to them up to three years of age. The level of supplement received was noted and the subsequent course of the children's development observed. Food supplementation of pregnant mothers was found to correlate with higher weights of their babies at birth. No other major maternal variables - home diet, body height and/or weight, morbidity, obstetric characteristics, or socioeconomic status - could account for this association.