Prosthetic conduits, with or without biological valves, are often inserted in surgical procedures to correct or palliate cardiac malformations. The principal problem is degeneration which causes variable degrees of obstruction requiring reoperation for their replacement. The aims of this study were to assess the feasibility, safety and efficacy of a non-surgical method of treating these obstructive prostheses by dilatation-implantation of a metallic vascular endoprosthesis (stenting). Thirteen patients were treated (age range 7.7 to 36 years; mean: 15 years). Eight had pulmonary atresia with a ventricular septal defect corrected by a valved conduit from the right ventricle to the pulmonary artery which became obstructive nearly 10 years later: the implantation of the stent reduced the transconduit pressure gradient in all cases except one who had not undergone closure of the septal defect in which the cyanosis was improved. There are two cases of obstruction of a modified Blalock anastomosis in which the stent revascularised the shunt with improvement in cyanosis. In the final 3 cases, the whole Fontan procedure was compromised by obstruction of a conduit incorporated in the system, and which dilatation with stenting considerably improved. The efficacy of the procedure was constant with no complications other than rupture of the balloon in 3 cases. The good results were maintained for an average of 7.3 months (range 1 to 25 months), but it was necessary to redilate one restenosed stent after 8 months. Dilatation followed by stenting in obstructive cardiovascular prostheses is a simple, safe and effective alternative to surgical reoperation.