We report the longest duration of implantation of a porcine bioprosthesis in the English language literature--a Carpentier-Edwards valved conduit excised after twenty-five years. This 50-year-old man had undergone a modified Fontan operation for tricuspid atresia. He presented with progressive dyspnea, fatigue and edema. The bioprosthesis' dysfunction was due to the pathologic findings of pannus, significant thrombus (on the sinus surface of a cusp), mild structural valve deterioration and pseudo-intimal formation within the conduit. The bioprosthesis' longevity is likely related to low-pressure circulation in the right heart and to host tissue (pannus) overgrowth that covered the cusps and thereby reduced tissue degeneration.