There is no published data regarding the financial impact of training orthopaedic residents in the operating room. No comparisons between orthopaedic faculty and residents in regard to operative time and costs are known. One hundred eleven cases of anterior cruciate ligament reconstruction with or without partial meniscectomy were evaluated from 1996 to 1997. Fifty-three cases met the selection criteria of times, documentation and identification of the surgeon. Twenty-one cases were performed by the orthopaedic attending (RCS) while 32 cases were performed by the senior orthopaedic resident. All procedures had the same faculty member present in the operating room either as the primary surgeon or as an assistant providing supervision and instruction as needed. In a two year period, comparisons were made between the attending and residents for the total anesthesia time and actual operative case time. Attending case time and anesthesia times averaged 94.62 minutes (range 60-125 min) and 128.1 minutes (range 84-185 min) respectively. Resident case and anesthesia times averaged 137.09 minutes (range 95-210 min) and 190.48 minutes (range 145-255 min) respectively. The anesthesia time was significantly less for the attending (p<.0001) as was the case time (p<.0001). The true costs of training orthopaedic surgery residents in the operating room is not known. The operative time and subsequent cost difference between experienced faculty and orthopaedic residents in certain arthroscopic procedures is not inconsequential. On average, the difference is equivalent to $228.73 per case for anesthesia costs. Based on increased operative times, operating room costs, on average, were increased by $661.85. The significant differences demonstrated between residents and faculty suggest the need to develop strategies and technical training facilities in order to improve orthopaedic residents' surgical skills and efficiency outside of the cost-central operating room.