As health care providers seek ways to reduce the cost of health care services, hospital operating rooms (ORs) have been identified as potential areas for cost reduction efforts. Cost containment efforts which have shifted significant portions of the inpatient population to ambulatory areas have resulted in an inpatient population which is sicker and more procedure-intensive. Efficient management of operating rooms has assumed even greater importance in this environment. Inefficient or inaccurate scheduling of OR time often results in delays of surgery or cancellations of procedures, which are costly to the patient and the hospital. Approaches to efficient use of ORs include computerized scheduling, utilization monitoring, and refinement of scheduling policies and procedures. In the absence of commercially available software to meet operating room management information needs, Johns Hopkins developed its own system in 1983. This software provides detailed information for daily OR management and long-term planning. The computerized operating room scheduling and monitoring system is described in this article and an operational measure of scheduling accuracy is proposed. Suggestions are made for incorporating this measure into planning and allocation decisions.