Surgical pathologic features of the tricuspid valve were reviewed in 363 patients who had undergone tricuspid valve replacement at our institution during the period 1963 through 1987. Valves were purely regurgitant in 74%, stenotic and regurgitant in 23%, and purely stenotic in 2%; two valves were neither stenotic nor regurgitant. Among 269 purely insufficient tricuspid valves, the four most common causes were postinflammatory disease (41%), congenital disorder (32%), pulmonary venous hypertension (21%), and infective endocarditis (4%). Of 92 cases of tricuspid stenosis, with or without regurgitation, postinflammatory disease was observed in 92%. Female patients accounted for 66% of the 363 cases, including 84% of those with postinflammatory disease and 64% of those with pulmonary venous hypertension. In contrast, male patients accounted for 73% of cases with endocarditis and 61% with congenital heart disease. Although postinflammatory disease accounted for 53% of the 363 cases, its relative frequency diminished from 79% during 1963 through 1967 to only 24% during 1983 through 1987. This trend may reflect the decreasing incidence of acute rheumatic fever reported in Western countries. During the same time interval, the relative frequency of congenital heart disease as a cause of tricuspid dysfunction increased from 7% to 53%, and it is currently the most common cause in our surgical population. This finding apparently reflects changes in patient referral practices and the development of new operative procedures.