BACKGROUND: The purpose of this study is to characterize variations in management late preterm infants because such variations in such a large group of neonates would have economic and health implications. METHODS: Comparison of the use of illustrative management approaches and gestational age at discharge among infants born at 33 to 34 6/7 weeks and discharged alive from 10 Massachusetts and California NICUs. RESULTS: Generally similar in birth weight and admission severity, significant differences were seen in illustrative interventions, such as the use of mechanical ventilation (range in use across hospitals from 9% to 43%) and nutritional practices (use of hyperalimentation ranged from 5% to 66%). Variations in average daily weight gain were seen with some infants averaging net losses. Postmenstrual age at discharge varied by a week between the hospital with the earliest discharge and that with the latest. CONCLUSIONS: Care for these infants would be improved by further examination of their needs and the establishment of practice guidelines to reduce unneeded variation.