Cognitive dysfunction has been widely studied in multiple sclerosis (MS), however decision-making has been less investigated. The current study examined the decision-making processes of patients with multiple sclerosis (MS) using a computerized version of the Iowa Gambling Task (IGT). This task was applied to 18 patients with clinically diagnosed MS and 18 healthy control subjects matched for age, sex, and years of education. The results showed that IGT scores differ significantly between patients with MS and the healthy control subjects: the patients with MS made significantly less advantageous decisions than the controls in the IGT. Possible causes of impaired decision-making in multiple sclerosis are discussed.