Background. The ideal resident call schedule remains unknown. This study assessed the impact of different call schedules on intern performance and education. Methods. A year-long, prospective, observational study of first- year residents in a surgery training program was performed with use of intern sleep/operative logs and questionnaires, and faculty questionnaires. Results. Compared with interns taking call every third or fourth night (and cross- covering a separate service), interns taking call every other night reported the greatest amount of fatigue and stress, the lowest satisfaction, and the fewest operative cases. Errors in patient care were not different between schedules. Multivariate analysis revealed that operative participation was inversely related to frequency of night call and level of fatigue post call, stress was related to fatigue while off call and service census, and overall satisfaction was associated with infrequency of call and operative cases performed. Faculty reported more errors by interns cross-covering other services and less operating room participation by interns taking call every other night. Conclusions. No single resident schedule optimally balances patient care and resident education and satisfaction. All 3 patterns of call studied are acceptable; specific decisions regarding the allocation of house staff manpower should be flexible and dependent on individual service and educational needs.