In view of contradictory reports on the growth hormone dependency of early postnatal growth we studied the growth curves of 15 infants with neonatal growth hormone deficiency. In seven infants the growth curve was parallel to the standards of the infancy-childhood-puberty (ICP) model (group 1), but in the remaining infants there was an immediate deviation of the growth curve (group 2). In this group the mean (SD) at 4 and 9 months of age was -3.3 (1.1) and -4.9 (1.4), respectively, when compared with the ICP model. The mean birth length in both groups was decreased and five out of 15 had a birth length of less than -2 SD. Serial measurements of the growth hormone response to provocation tests in two patients in group 2 showed decreasing concentrations, while four patients with documented complete growth hormone deficiency belonged to group 2. We conclude that growth hormone is needed for early infant growth and that the normal growth pattern in some infants with neonatal pituitary dysfunction is due to incomplete insufficiency.