The failing Fontan circulation presents difficult treatment challenges. When Fontan revision and or intervention for treatable arrhythmias are not feasible, heart transplantation is the only therapeutic option. Particular challenges presented by these patients include limited ability to assess hemodynamics, complex anatomy, multiple prior procedures, and unique underlying pathologic states. These issues complicate the decision-making process for further surgical intervention verses transplantation. The pretransplant evaluation, transplant operation, and postoperative management are more problematic for these patients compared with most patients undergoing transplantation. Consequently, failing Fontan patients constitute one of the highest risk heart transplant subsets.