Wilson's disease is a genetic disorder characterized by accumulation of copper in many organs and tissues. Phenotypic manifestations are wide-ranging from neuropsychiatric disorders, to severe liver disease requiring liver transplantation. Clinical presentation is not often related to the genetic defect and siblings may have different type of disease. Liver transplantation is indicated for all patients with Wilson's disease and decompensated liver cirrhosis unresponsive to medical therapy, but its efficacy in resolving the neurological symptoms is still controversial, because as far now, very different outcomes have been reported. We describe here on the exceptional case of two homozygotic twins, both with liver cirrhosis due to Wilson's disease, one of them with severe neuropsychiatric involvement, who both underwent liver transplantation and subsequently had very different outcome despite same genetic background. The presence of neurological clinical manifestations in Wilson's disease should recommend caution indicating liver transplantation, because irreversible brain damage may exist.