We asked whether surgical process and outcome differ for physicians in postgraduate training supervised by attending surgeons compared with attending surgeons alone. All appendectomies performed during a 2 year period in a 320 bed voluntary hospital where either the admitting diagnosis or the preoperative diagnosis suggested acute appendicitis were included in the study. Data were abstracted from medical records and pathology reports. One hundred fifty-four cases of primary appendectomy were reviewed. In 97 cases, 1 of 9 attending physicians was listed as chief surgeon; in 57 cases, 1 of 15 resident physicians was listed as chief surgeon. There were no significant differences between the two patient groups according to age and sex. There was no difference between attending resident physicians in accuracy of diagnosis. Despite a pathologically normal appendix, attending surgeons in six cases and residents in two cases listed a discharge diagnosis of appendicitis. The average length of stay was 8.8 days for attending surgeons' cases and 7.1 days for residents' cases (t = 1.09, p = 0.29). The postoperative complication rates were 24 percent for attendings' cases and 12 percent for residents' cases (chi-square = 2.31, p = 0.16). We conclude that there is no appreciable difference in either the process or the outcome of care for patients undergoing appendectomy whether the operation is performed by an attending physician or a resident physician supervised by an attending physician.