Despite its many anatomic modifications, Fontan failure remains prevalent in adult patients living with single-ventricle physiology. Although the Fontan operation has created a generation of survivors of complex single-ventricle disease, recognition of the limitation of this circulation is increasing. Most commonly, survivors suffer from ventricular dysfunction, protein-losing enteropathy, plastic bronchitis and arrhythmias. Although several medical therapies exist to palliate these long-term complications, surgical treatments are becoming increasingly useful, including the introduction of mechanical devices and cardiac transplantation. Currently, there are a variety of options available for mechanical support of the failing Fontan. Further developments in mechanical support technology will be required to tailor-make specific devices for this unique population. Owing to the fact that availability of donor hearts for transplantation is limited, mechanical support will play an increasingly important role in the management of complications of the Fontan circulation.