Criteria for classification of symptomatic osteoarthritis (OA) have been developed by a Subcommittee of the American College of Rheumatology. Criteria for symptomatic OA of the knee, hand and hip have been developed. Different sets of criteria were developed for different investigative purposes: (1) clinical (history and physical examination), (2) clinical and laboratory, and (3) clinical, laboratory and radiographic changes. It is recommended that criteria for classification of symptomatic OA be used in patients to be evaluated in clinical trials, population surveys, and in reports dealing with patients who have symptomatic OA of the knee, hand and hip.