Univentricular heart (UVH) is a complex and congenital cardiac malformation that both atria are connected to a functional single ventricle (1). The prognosis is poor when this malformation is not operated (2). Although rare cases have been reported in literatures, surviving into adulthood without surgery is mostly difficult. This article is about an adult patient with single ventricle who was not operated, but the patient had a prosthetic valve and the coexistence of these two situations make the case very interesting.