['Allocation of operating room (OR) block time is an ongoing challenge for OR managers. In this study, we sought to determine whether inclusion or exclusion of turnover time in comparisons of block utilization would identify different surgical services as under- or overused. For a 13-mo period, we evaluated data extracted from the OR information system of a large academic medical center. During that time period, 15 surgical services performed 12,245 surgical procedures. Allocated block hours, number of first cases performed, total number of cases, and average case durations were determined. The average turnover time for each service was determined by a manual, case-by-case review of data from 1 mo. Raw utilization (RU; case durations only) and adjusted utilization (AU; case duration plus turnover time) were calculated for each service. Turnover time was credited to the service performing surgery after room turnover. Case du-ration was limited to surgeries performed during resource hours. Two indices of utilization (i.e., the usage rate of the service divided by the overall use of all ORs in the suite) were used to compare services: the RU or AU Index (RUI or AUI). Outliers were services with indices that were >1.15 or <0.85. The RUI identified three services as underutilizers and one service as an overutilizer. Using the AUI, the same outliers were identified, and no new services were identified. Examining the changes in index (between AUI and RUI), the percentage of to-follow cases highly correlated with changes in index (r(2) = 0.60); the average turnover time did not (r(2) = 0.002). Inclusion of turnover time did not change the services that were identified as under- and overutilizer.'] Does inclusion of turnover time influence identification of surgical services that over- and underutilize allocated block time?