QUALITY IN MEDICAL CARE is fundamental; however, the recognition of quality is a complex task. The Patterns of Care Study is examining radiotherapeutic care in cancer throughout the United States, using a new methodology which can be applied to other medical disciplines. The system is described and illustrated as applied to the management of carcinoma of the cervix. Considerable variations in treatment have been identified. These variations can be studied and, where necessary, modified by appropriate educational programs; thus, the quality of medical care can be improved.