PURPOSE: The purpose of this study was to compare the costs associated with anterior cruciate ligament (ACL) reconstruction with either bone-patellar tendon-bone (BPTB) autograft or BPTB allograft. METHODS: Surgical costs are reported, including supply costs, based on invoice costs per item used per procedure, and personnel costs calculated as cost per minute. All operations were performed at an ambulatory surgery center between March 2005 and March 2006. A total of 160 patients underwent primary ACL reconstruction with either BPTB autograft (n = 106) or BPTB allograft (n = 54). Procedure cost data were retrieved from a financial management database and divided into various categories for comparison of the 2 groups. Payment data were provided by the surgery center's billing office. RESULTS: The total mean cost per case was $4,147 +/- $943 in the allograft group compared with $3,154 +/- $704 in the autograft group; this was statistically significant (P < .001). The mean operating room time was 12 minutes greater in autograft cases (P = .006). Supply costs comprised a mean of 58.7% of total expenses in the autograft group and 72.2% in the allograft group. CONCLUSIONS: Allograft reconstruction of the ACL was significantly more expensive than autograft reconstruction. LEVEL OF EVIDENCE: Level II, economic analysis.