We treated eighteen non-ambulatory patients by multiple operations consisting of total replacement of the hip or the knee, or both. Thirteen patients had rheumatoid arthritis, four had degenerative arthritis, and one had had bilateral resection of the femoral head and neck. The patients were followed for an average of forty months. We devised a classification based on the number of joints involved and a rating scale for function. Good to excellent results were achieved in the patients who had two or three joints operated on (with one exception). Fifteen patients became ambulatory and seven could climb stairs. Seven patients were pain-free. The factors responsible for poor results were significant neural problems and loss of motivation. The presence of severe upper-extremity involvement was not an obstacle preventing walking.