A study of the effects of restricted vs. unrestricted maternal caloric intakes upon infant birthweights was conducted in a large, middle-class, private obstetrical practice in Madison. Wis. Comparison of data relating to 602 pregnancies showed that increases in maternal weight gain accompanied significant and desirable increases in infant birthweight. Findings in this study support the statement of the Food and Nutrition Board that caloric restriction during pregnancy may be undesirable and probably is detrimental to the newborn.