BACKGROUND: Adult patients who do not fulfill the classical Fontan criteria now undergo total cavopulmonary connection (TCPC). However, limited information is available on the results for high-risk adult TCPC. METHODS: Twenty-five consecutive adult patients (aged 16 years or more) who underwent TCPC were retrospectively reviewed. The mean age at operation was 27 +/- 9 years (range, 16 to 52). The following items were considered as the potential risk factors according to previous reports: (1) aged more than 30 years (7 of 25); (2) heterotaxy (9 of 25); (3) systemic ventricular ejection fraction less than 50% (6 of 25); (4) atrioventricular valve regurgitation moderate or greater (6 of 25); (5) pulmonary arterial index less than 200 (7 of 25); (6) mean pulmonary arterial pressure 15 mm Hg or greater (3 of 25); (7) pulmonary arterial resistance 2.0 wood units or greater (11 of 25); (8) arrhythmias (13 of 25); (9) protein-losing enteropathy (3 of 25); (10) New York Heart Association (NYHA) functional class III or greater (9 of 25); (11) previous Fontan procedure (10 of 25); (12) systemic ventricular outflow obstruction (1 of 25); and (13) end-diastolic pressure of the systemic ventricle 11 mm Hg or higher (4 of 25). RESULTS: The mean follow-up period was 57 +/- 45 months (range, 0 to 154). All patients had at least 2 risk factors (range, 2 to 8). There was 1 early death and 2 late deaths. Comparing the late survivors and nonsurvivors, no statistical significance was identified in the above risk factors. However, the patients with 6 or more risk factors had a significantly higher mortality rate than patients with fewer than 6 risk risk factors (p < 0.01). Age (p = 0.08), NYHA class (p = 0.13), and protein-losing enteropathy (p = 0.08) may be risk factors for late death. CONCLUSIONS: The majority of the adult TCPC candidates tolerated the TCPC procedure in the early postoperative period. However, the accumulation of risk factors influences late mortality.