Objective: We investigated whether alexithymia is at the root of the decision-making deficit classically reported in pathological gamblers. Background: Alexithymia has been shown to be a recurrent personality trait of pathological gamblers and to impair the decision-making abilities of nonpathological gamblers, but no previous studies have investigated whether alexithymia significantly affects pathological gamblers' decision making. Although investigations of pathological gamblers typically have studied those seeking treatment, most pathological gamblers do not seek treatment. Thus, to study people representative of the general population of pathological gamblers, we conducted our study in "sportsbook" casinos with a small sample of gamblers who were not seeking treatment. Methods: We recruited gamblers in sportsbooks and classified them based on their scores on the South Oaks Gambling Screen and the Toronto Alexithymia Scale: 3 groups of pathological gamblers (6 alexithymic, 8 possibly alexithymic, and 6 nonalexithymic) and 8 healthy controls. All of the participants completed an adaptation of the Iowa Gambling Task. Results: The alexithymic group chose less advantageously on the task than the other groups. The severity of the deficit in decisionmaking abilities was related to the severity of alexithymia, even when we controlled for the effects of anxiety and depression. Conclusions: Our findings provide preliminary evidence that alexithymia might be a critical personality trait underlying pathological gamblers' decision-making deficits.