The Kudo prosthesis is the most commonly used elbow implant in Sweden. However, there are few reports of the results, besides those reported by Kudo himself. I have implanted 30 Kudo type 4 or 5 elbow prostheses in 28 patients with rheumatoid arthritis. 3 arthroplastics were revised, 2 because of loosening and 1 because of a periprosthetic ulnar fracture. 6 major peroperative or early postoperative complications occurred, but only 1 of these was a failure. 2 patients developed postoperative ulnar neuropathy, one was transient and the other patient died 1 year after surgery. 26 elbows were available for follow-up at an average 5 (2-8) years after implantation. All 26 functioned well although radiographic loosening of the humeral component was found in 1 patient. The average range of flexion increased by 14 degrees while the extension lag was unchanged (35 degrees). Activities of daily living had improved markedly and all but 3 patients were satisfied with their elbow. Radiolucent lines were seen around the proximal part of the ulnar component in 18/26 elbows. Although progressive in 1 patient only, this is a matter of concern, indicating that this component may be the weak part of the Kudo prosthesis.