Substance-dependent individuals (SDIs) often show neurocognitive deficits in decision-making, such that their choices are biased toward the greatest immediate reward rather than the optimal future outcome. However, studies of SDIs are often hampered by two significant methodological challenges: polysubstance dependence and comorbid conditions, which are independently associated with neurocognitive impairments. We addressed these methodological challenges by testing heroin addicts in Bulgaria, where heroin addiction is highly prevalent but polysubstance dependence is rare. The goal of the current study was to evaluate the potential contribution of psychopathy to decision-making processes among this group of Bulgarian heroin addicts. We tested 78 male currently abstaining heroin addicts, classified as psychopathic or non-psychopathic using the Hare Psychopathy Checklist, Revised (PCL-R). Psychopathic heroin addicts showed notable deficits in decision-making in that they made significantly more disadvantageous decisions relative to non-psychopathic heroin addicts. Results indicate that the presence of psychopathy may exacerbate decision-making deficits in heroin addicts.