Thirty-five porous-coated total hip arthroplasties were implanted in 25 patients with juvenile-onset or adult-onset rheumatoid arthritis and prospectively followed for a mean of 4.5 years (range, 3–6.5 years). Using the Harris hip rating, the mean hip score at the final follow-up evaluation was 91, and 86% of the hips had a good or excellent result. Thirty-one hips had no hip or thigh pain, while four had occasional slight pain. After surgery, 10 patients were employed and the remainder were ambulatory. There were no early or late deep infections. There was one reoperation for recurrent dislocation of the hip, but the components were not removed. Radiographic evaluation of the acetabular component showed that only one component had a complete radiolucent line in all three zones. Three femoral components had nonprogressive subsidence. At this intermediate-term follow-up period, porous-coated total hip arthroplasty is a promising technique that is likely to be successful in young patients with rheumatoid arthritis.