From April, 1975, to October, 1985, 50 patients (mean age, 5.3 years; range, 2.5 to 14 years) underwent a Fontan repair for tricuspid atresia or severe tricuspid stenosis. Fifty-six palliative operations had been performed previously in 43 patients. Twenty-nine patients received an atriopulmonary connection by direct anastomosis [19], interposition of an aortic homograft [7], or a porcine heterograft [3]. An atrium-subpulmonary chamber connection was performed in 21 patients (Björk modification, 10; Dacron tube, 10; valved conduit, 1). Eleven patients (22%) died early, 6 of whom did not meet the established criteria for a Fontan operation. One patient died 6 months postoperatively of superior vena cava thrombosis. Four patients were reoperated on successfully. At a mean follow-up of 28.8 months, 28 patients are in New York Heart Association Functional Class I and 9 are in Class II; 1 patient was lost to follow-up. Thirteen patients underwent control catheterization fifteen days to four years postoperatively (median right atrial pressure, 14 mm Hg). Exercise testing in 9 asymptomatic patients, performed after a mean interval of 33 months, showed a moderate impairment of cardiac performance. We conclude that in select patients, a Fontan repair appears to be a reliable procedure at medium-term follow-up.