Mind-wandering refers to the intentional and unintentional tendency to withdraw from the external environment and engage in internally generated thoughts. We investigated intentional and unintentional mind-wandering in patients with Korsakoff syndrome (KS). We invited 31 patients with KS and 33 control participants to answer a questionnaire probing intentional and unintentional mind-wandering. Analysis demonstrated higher intentional and unintentional mind-wandering in patients with KS than in controls. However, no significant differences were observed between intentional and unintentional mind-wandering in patients with KS or in controls. Significant positive correlations were observed between intentional and unintentional mind-wandering and depression in patients with KS but not with cognitive controls. Our results demonstrate a high intentional and unintentional tendency in patients with KS to shift attention away from the external environment to internal thoughts/feelings that are unrelated to the ongoing task. This tendency may be associated with the activation of negative thoughts/beliefs, as observed in depression.