Tricuspid valve replacement is not a common operation, The purpose of this study was to examine the early and late results in 60 patients who underwent 28 (47%) bioprosthetic and 32 (53%) mechanical tricuspid valve replacements, All operations took place between January 1978 and June 1993 during which period a total of 4741 patients underwent valve replacement operation, Mean patient age was 50 +/- 15 (18 to 75) years, Forty-one patients (68%) were female and 19 patients (32%) were male, Forty-nine patients (82%) were in New York Heart Association class III or TV before operation, Forty-five patients (75%) were undergoing repeat cardiac valve operation, Seventeen patients (28%) had complex congenital cardiac problems, Operation was urgent in 15 patients (25%), The hospital mortality rate was 27% (16 patients), All patients with hospital death were in New York Heart Association class III or IV,were having repeat operations, or had complex congenital disease, Low output syndrome was observed in 21 patients (35%), Reoperation because of bleeding was required in seven patients (12%), Thirteen patients (22%) required permanent (epicardial lead) pacemaker implantation, Mean follow-up is 75 +/- 45 months (maximum 173 months) and 100% complete for the 44 patients who left the hospital, There have been 14 deaths (32%), Nine of these patients (64%) had mechanical valves and five (36%) had bioprostheses, Of the 11 cardiac deaths, three were valve related (bioprostheses), Three patients (10%) required reoperation because of tricuspid valve prosthetic failure (1 thrombosed mechanical valve, 2 failed porcine valves), Of the remaining 30 patients, 20 (67%) are in New York Heart Association class I or II, Seventeen patients have mechanical valves and 13 have bioprostheses. Twenty-six patients (90%) are receiving warfarin, Thromboembolism (transient ischemic attack) has occurred in one patient with a mechanical valve who also had a previous cerebrovascular accident, In this group there has been no hemorrhage, endocarditis, or new pacemaker requirement, Actuarial survival for the whole series is 37% +/- 9% and for the hospital survivors is 50% +/- 12% at 15 years, Linearized rates of valve-related complications are not different between groups, Tricuspid valve replacement is a beneficial procedure for patients with structural tricuspid valve disease, many of whom have other valvular or congenital disease, Contemporary mechanical prostheses and bioprostheses are equally effective in the tricuspid position, Mechanical valves should be considered for tricuspid replacement in young patients and in patients with mechanical valves implanted in the left side of the heart.