PURPOSE: Since the successful application of total atrio-pulmonary connection(TAPC) to patients with various types of physiologic single ventricles in 1971, post-operative survival rates have reached more than 90%. However some patients have been shown to present with late complications such as right atrial thrombosis, atrial fibrillation and protein losing enteropathy eventually leading to re-operation to control the long-term complications. The aim of this study is to review the results of total cavo-pulmonary connection(TCPC) in cases with late complications after TAPC. METHODS: Between Jan. 1995 and Dec. 2000, 6 patients(5 males and 1 female) underwent cardiac catheterization 11+/-3 months after conversion of previous TAPC to TCPC. We compared the hemodynamic and morphologic parameters before and after TCPC and also assessed the clinical outcomes. The indications for TAPC were tricuspid atresia in 4 cases and complex double-outlet right ventricle with single ventricle physiology in 2 cases. RESULTS: There was no peri-operative mortality and all patients were clinically and hemodynamically improved at a mean follow-up of 11 months(range: 4 to 13). However, protein losing enteropathy recurred in 2 patients; this was were successfully treated with subcutaneous administration of heparin. Right atrial pressure before TCPC was 18.0+/-3.6 mmHg, but baffle pressure, corresponding to right atrial pressure decreased to 14.8+/-3.6 mmHg after TCPC. The size of the pulmonary arteries did not regress after TCPC. CONCLUSION: The conversion of TAPC to TCPC improves clinical and hemodynamic status by decreasing the right atrial pressure and by providing a laminar cavo-pulmonary flow which enhances the effective pulmonary circulation in the so-called Fontan circulation.