Wilson's disease (WD) causes deposition of copper, mainly in the basal ganglia. One consequence of deposition seems to be impairment of executive functions, which could cause problems in decision making. In 30 WD patients and 30 healthy controls (HCs), we examined decision making under risk in the Game of Dice Task, and we assessed working memory and executive functions. WD patients exhibited a greater preference for disadvantageous choices than did HCs. Reduced decision-making performance was closely correlated to lower executive functions. Decision-making deficits of WD might be associated with frontostriatal loops, which are involved in executive functions and feedback processing.