Hospital care costs may vary depending in part on differences in background and level of training of providers. In this teaching hospital nursery, teams of pediatric and family medicine interns supervised by neonatal nurse practitioners (NNP) or senior pediatric residents (RES), directed by the same attending physician, provide care. Patients (pts) are alternately assigned to a team regardless of severity of illness, and ≈15% of pts are cared for by NNPs directly. To evaluate potential cost-containment strategies in this setting, we tested the hypothesis that NNP and RES supervised care would differ in length of hospital stay (LOS) and/or total hospital charges. Admissions to the level II or III nurseries at one university hospital were reviewed for the year 1994. LOS (discharge date minus birth date) was determined for all infants of gestational age (GA) ≤ 34 weeks. Survival analysis censored for pt deaths, discharge transfer to other units, or major congenital anomalies. Total hospital charges (excluding physicians' fees) came from the hospital pt database. A Kaplan-Meier estimate of the survival function was used; NNP and RES pt groups were compared by the Mantel-Cox logrank test. 131 pts were admitted, with 101 uncensored; charges were available for 100. GA and birth weights were similar in both groups: means 31 wks and 1415 g for NNP vs 30.5 wks and 1311 g for RES. There wereno differences in the survival curves generated by either NNP(n=53) or RES (n=48) patient stays. Average LOS was 43.2 ± 3.5 d for NNP vs 42.6 ± 4.5 d for RES. Hospital charges, total (survival analysis) and daily (unpaired t-test), also did not differ: mean total and daily charges were $70,321 and $1,572 for NNP vs $71,265 and $1,478 for RES. We conclude that care provided by pediatric trainees has no adverse impact on LOS or total hospital charges compared to care supervised by NNPs in this teaching setting. Strategies to contain costs should be directed at specific elements of treatment, i.e. earlier discharge with home nursing care, regardless of the personnel who apparently provide similar cost-effective care.