Heroin addicts on 0 or 2 mg of methadone and finishing a 14-day detoxification program, and control subjects were shown a videotape of heroin-related stimuli. Psychological questionnaires were completed before and after the videotape, while physiological responses were monitored during viewing. It was found that the experimental subjects had an increased level of anxiety, depression, and subjective level of craving following the stimulus presentation, with the controls showing no similar change in these measures. In addition, the experimental group had significant increases in heart rate and galvanic skin response compared with controls. The results present some of the first objective evidence of conditioned abstinence occurring in addicts exposed to stimuli closely related to those found in the natural environment.