From December 1988 to December 1991, 100 patients underwent valve replacement with a Carbomedics bileaflet valve in our institution (55 aortic valve replacements, 28 mitral valve replacements, and 17 double valve replacements). Fifty-nine percent were males. Mean age was 55.7+/-12.3 years. Fifty eight percent of patients were in NYHA Clinical status III or IV. Operative mortality was 3% (3/100). All patients but one were followed up for an average of 2.8 years after their operation and total follow-up was 280 patient years. At the time of the study, more than 80% of patients were in NYHA class I or II, 34% were in atrial fibrillation and 100% of patients received anticoagulation treatment. There were 3 late deaths. After 4 years, the actuarial survival rate was 94%+/-5%. No patients died of valve-related causes. Valve-related complications included 2 thromboembolic episodes (0.7%-patient-year), 8 anticoagulant-related complications (2% patient-year), and one reoperation (0.3% patient-year). After 4 years, freedom from thromboembolic complication was 96%+/-4%, from endocarditis was 100%, from reoperation was 99%+/-1%, and from anticoagulant-related complications was 93%+/-5%. We conclude that the 4-year results compare with other bileaflet valves. More follow-up and larger studies are mandated to give definite conclusions.