The blood glucose and plasma FFA content and composition of the newborns of normal women, gestational diabetics, and insulin-dependent diabetics were analyzed. Normal maternal FFA levels were twice the fetal values; by 2 hours of age FFA increased fourfold over initial values in normal infants, while infants of gestational diabetics had a threefold rise, and those of insulin dependent diabetics only twofold. Blood sugar at the same time decreased, and there was an inverse relationship between blood glucose in the normal infants and FFA. This relationship is altered in the infant of the diabetic mother. Gas chromatography of plasma indicated a higher ratio of unsaturated to saturated FFA in mothers compared to infants. No pattern differences were noted between the normal and diabetic mothers, except that the latter had higher oleic acid. In the initial 2 hours of life, the patterns changed, although no differences were noted between infants of diabetic mothers and normals. The observations suggest: (1) The metabolic interrelationships of glucose and FFA in the normal infant are different from those in the infant of the diabetic mother. The latter infant has a state of physiological hyperinsulinism. (2) Plasma FFA in the fetus is derived from both fetal fat synthesis as well as placental transfer. (3) The infant of the diabetic mother does not differ from the normal as regards FFA composition.