A unique case of a focal nodular hyperplasia (FNH) in identical twins is presented. The computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen demonstrated in both twins a mass of identical size in the same segment of their liver. Histopathologic examination of both masses confirmed the diagnosis of focal nodular hyperplasia. This case report strongly supports the theory of a congenital vascular anomaly playing a major role in the etiology of focal nodular hyperplasia.