The number of deciduous teeth in a sample of rural Ladino Guatemalan children was counted every 3 mth through 24 mth of age, and at 6 mth intervals from 24 to 36 mth. Nutritional status at birth, whether expressed as full term birth weight or as maternal caloric supplementation during pregnancy, influences the timing of deciduous tooth eruption. Furthermore, the timing of deciduous tooth eruption seems more closely associated with postnatal weight than with birth weight. Although indices of nutritional deficiences are associated with retarded tooth eruption, the use of mean number of deciduous teeth erupted as an estimate of mean chronological age in populations living under conditions of mild to moderate malnutrition is relatively accurate because errors of age estimation based on mean values for the present sample only vary between 1 and 2 mth.