Follow-up has been achieved in 41 hospital survivals who received xenograft valved conduits in the pulmonary position. The interval after operation ranged 6 months to 13 years (average 5.2 +/- 3.7 years) (+/- standard deviation). There has been 8 late deaths, 3 of which were sudden. Of the 11 reoperations, 7 underwent graft replacement with no operative death. The actuarial reoperation free survival rate was 73% at 5 years, and 54% at 10 years. There was a significant correlation between the interval after operation (x years) and the pressure gradient across the conduits (y mmHg). (y = 20.7 + 9.7x, r = 0.74, p < 0.001). Balloon dilatation of the conduits was performed in 15 patients. The mean conduit gradient was significantly (p < 0.001) reduced from 85 +/- 29 to 54 +/- 22 mmHg. However, the effect was not satisfactory enough and 4 patients received graft replacement after the balloon dilatation. These results warrant the avoidance of xenograft valved conduits in the pulmonary position, the safety of the graft replacement, and the limitation of the balloon dilatation for the stenosed conduits.