Objective: The aim of this study was to examine the effects of a newly established neonatal intensive care unit (NICU) on clinical work practice and educational activity at Nippon Medical School Musashikosugi Hospital. Methods: This retrospective study analyzed the clinical records of all neonates admitted to the NICU from December 2010 through November 2013. Anthropometric data, clinical status, problems, and outcomes of patients and the related obstetrical history were extracted and analyzed. Results: Of the 568 neonatal admissions, about half were related to preterm birth (49%) and low birth weight (55%). Forty-eight percent of patients were born via caesarean delivery. Maternal hypertension, diabetes, and thyroid disease were found in 8%, 5%, and 2% of cases, respectively. Mechanical ventilatory support was provided for 20% of patients. Neonates from multiple pregnancy and with significant congenital anomalies accounted for 17% and 10% of all patients, respectively. Five patients died during hospitalization. In addition training was provided in the NICU for an average of 10 residents and 20 medical students per year. Conclusion: Since the NICU was established, closer cooperation beyond the framework of a single department has come to be needed. In addition, NICUs in teaching hospitals are expected to provide opportunities for medical students and residents to observe and participate in multidisciplinary medical care.