This study examined the effects of naltrexone (50 mg/day) on mood and self-reported desire for alcohol and cocaine in 26 patients with comorbid alcohol and cocaine abuse/dependence. Two laboratory sessions were conducted, separated by 1 week. During the sessions, subjects viewed 5-min films containing either cocaine, alcohol, or neutral cues. The first session occurred prior to random assignment to medication group and the second session was held after 1 week of double-blind treatment with either naltrexone or placebo. The cocaine-related film induced a greater desire to use cocaine than the desire for alcohol that was induced by the alcohol-related film. This finding was observed using both a simple, one-item analog scale administered during the films and more complex craving questionnaires administered immediately after the films. Collectively, the alcohol and cocaine-related films evoked greater levels of self-reported anxiety and elation, and lower levels of concentration, than the neutral film. Naltrexone did not differ from placebo in reducing the desire to use either cocaine or alcohol.