OBJECTIVES: To assess risk-adjusted early (within 7 days) mortality and major morbidities of newborn infants at < 32 weeks' gestation who are admitted after office hours to a regional Australian network of NICUs where statewide caseload is coordinated and staffed by on-floor registrars working in shift rosters. We hypothesize that adverse sequelae are increased in these infants. DESIGNS: We conducted a database review of the records of infants (n = 8654) at < 32 weeks' gestation admitted to a network of 10 tertiary NICUs in New South Wales and the Australian Capital Territory from 1992 to 2002. Multivariate logistic regression analysis was performed to adjust for case-mix and significant baseline characteristics. OUTCOMES: Sixty-five percent of infants were admitted to the NICUs after hours. These infants did not have an increase in early neonatal mortality or major neonatal sequelae compared with their office-hours counterparts. Admissions during late night hours after midnight or fatigue risk periods before the end of a medical 12-hour shift were not associated with higher early mortality. Risk factors significantly predictive of early neonatal death were lack of antenatal steroid treatment, Apgar score < 7 at 5 minutes, male gender, gestation age, and being small for gestation. CONCLUSIONS: Current staffing levels, specialization, and networking are associated with lower circadian variation in adverse outcomes and after-hours admission to this NICU network and have no significant impact on early neonatal mortality and morbidity.