The aim of this study was to investigate the longterm results of isolated pulmonary valve replacement using xenobioprostheses or mechanical valves. Twenty-four cases of isolated pulmonary valve replacement carried out at Kyushu University Hospital between 1977 and 2004 were reviewed. Those undergoing Rastelli's operation were excluded from this study. Bioprostheses were used in 18 patients and mechanical valves in 6. There were no operative deaths. Two patients with mechanical valves needed repeat pulmonary valve replacement due to thrombosed valves. The patients with bioprostheses had no need of repeat replacement postoperatively. The cardiothoracic ratio significantly improved from 60.3% preoperatively to 55.4% postoperatively (P < 0.05), and the New York Heart Association (NYHA) class significantly improved from 2.0 preoperatively to 1.1 postoperatively (P < 0.05). The actuarial survival rate at 15 years was 92.3%. The valve-related event-free ratio at 15 years was 85.7% in the bioprosthesis group and 66.7% in the mechanical valve group, with no significant difference. Isolated pulmonary valve replacement with bioprostheses or mechanical valves can be safely done and showed satisfactory long-term results. The mechanical valve group demonstrated a high ratio of thrombosed valves. A bioprosthesis is recommended for pulmonary valve replacement if a homograft is not available.