The benefits of multiple joint replacements were assessed in 21 patients with rheumatoid arthritis who had bilateral hip and knee replacements. The main benefit was relief of pain with 40 hips and 25 knees becoming completely pain-free. There was an improved range of movement in 38 hips but in only 11 knees and 8 knees were stiffer after surgery. Hip replacement was the preferred initial surgery but there was a mean delay of 50 months between hip and knee surgery suggesting a "domino effect" with increasing mobility as a consequence of hip replacement eventually causing knees to deteriorate. All patients who completed a postal questionnaire found their ability to walk had improved but many noted an increase in ankle and foot pain which limited their walking. After their surgery patients were better able to perform certain activities of daily life, especially housework and dressing. It is concluded that multiple joint replacement contributes to improving the quality of life in disabled arthritic patients.