Temperatures for rewarming neonates have been established for convection incubators. The purpose of this study was to evaluate the effects on neonates when the skin surface was rewarmed at one of four different levels with an infra-red warmer. A total of 42 normal term neonates were first divided into four groups according to deep rectal temperature on admission; infants in each of the respective groups were then allotted to one of the following skin surface temperature set-point groups: 35, 36, 37 or 38 degrees c for rewarming under a servo-controlled infra-red heat source. Although rewarming at 38 degrees (100.4 degrees F) surfacetemperature bears the theoretic risk of the effects of hyperthermic stress to the neonate, particularly of apnea, the 12 infants rewarmed at this temperature set-point all achieved normal rectal temperatures significantly sooner than the infants in the other three groups without evidence of ill effects. The attainment of a rectal temperature of 37 degrees C within the 4 hr study period and the absence of hypoglycemia in the 38 degrees C skin temperature group was statistically significant when compared to the frequency of occurrence in the other groups.