Evaluation of risk factors and short-term outcomes in the neonatal intensive care unit (NICU) are essential to identify infants in need of developmental intervention after discharge. This study examined risk factors with the potential to affect short-term neurobehavioral and sleep outcomes in preterm infants born at <31 weeks gestation. Data were obtained in a larger longitudinal randomized study of the effects of cycled light and continuous near darkness on health. Severity of neurological insults and caffeine use predicted poorer neurobehavioral outcomes; and severity of neurological insults, caffeine use, length of hospitalization and ventilator days were associated with altered sleep-wake state organization. There were no significant effects of environmental lighting on the short-term developmental outcomes of preterm infants. Early knowledge of an infant's neurobehavioral and sleep outcomes can provide families and health care providers with important information to target the utilization of early intervention services. © 2005 Elsevier Inc. All rights reserved.