A classification system for surgical patients and a quantitative index of services have been developed to determine the resources utilized for medical care in an urban hospital emergency department. Five classes of surgical patients based on patient management reflect the amount of diagnostic and therapeutic work performed. Quantitative estimates of workload and rates at which services are delivered to each patient class are included. This classification of patients which is derived from a natural grouping of common patient problems with common patterns of management, can be an important aid to effective analysis and planning of medical care in outpatient settings.