Records of 762 infants weighing less than 2,500 gm at birth and born after 37 to 44 weeks' gestation—small-for-dates neonates—were compared with records of infants with similar birth weight born after 28 to 32 weeks' gestation—pre-term infants—and with records of infants weighing 3,000 to 3,500 gm born after 37 to 44 weeks' gestation—"average" infants. Records were compared with regard to maternal and gestational features, perinatal survival, and neonatal complications. The group of small-for-dates neonates differed markedly from the pre-term infants in 15 of the 35 variables examined and from the "average" infants in 31 of the 35 variables examined. Small-for-dates infants showed a higher incidence of maternal toxemia and hypertension, a greater incidence of primiparous mothers, a lower incidence of gestational bleeding, a lower incidence of low-birth-weight siblings, fewer neonatal complications and deaths, and a lower incidence of hemolytic disease and pulmonary disease in the newborn period than did weight-matched pre-term controls. Gestational age, though subject to error in measurement, is as important a predictor of neonatal clinical status and outcome as is birth weight. Future studies of the antecedent conditions, neonatal course, and longterm outcome of low-birth-weight infants must consider both birth weight and gestational age.