A study of 41 rheumatoid knees demonstrated significant (P =.05) relationships between the gait characteristics of knee motion during walking, cadence, and stride length with the severity of pain, status of the articular surface, flexion contracture, standing flexion, range of motion, varus-valgus deformity, and abnormality of the contralateral foot. Synovial thickness, effusion, and ligamentous instability did not significantly alter gait. The rheumatoid knee used less of the available motion in walking than did normal knees, 25.2% compared to 46%. Standing knee flexion exceeded fixed flexion deformity in 20 knees and varied from 14° to 40° in four knees without flexion deformity. Quantitative evaluation of the significant clinical features provides an indirect method of assessing knee function.