St. Jude Medical bileaflet valve replacement was performed on 182 patients--aortic in 90, mitral in 70, both sites in 20 and tricuspid in two. The 30-day mortality was 4.3%, and was related to poor preoperative condition (NYHA class III or IV). The late mortality during observation up to 8 years was 9.3%, with actuarial survival 87.4% at 5 years and 86.3% at 8 years. For aortic, mitral and double valve replacement the respective 8-year figures were 88, 87.3 and 76.2%. Late death was associated with high preoperative pulmonary vascular resistance in five cases, dysrhythmia in four, myocardial infarction in two, thromboembolism, paravalvular leakage, prosthetic endocarditis or bleeding, each in one case, and was accidental in two cases. Calculated per 100 patient years the incidence of late thromboembolic events was 1.0, of bleeding complications 0.9 and of prosthetic valve endocarditis and paravalvular leak 0.26 (8, 7, 2 and 2 cases). The NYHA class in the 144 cases available for follow-up was I in 63%, II in 27% and III in 10%. The St. Jude Medical prosthesis thus was reliable, with good long-term performance.