Aims: Consistent with the opponent process theory individuals with chronic opioid use should predominantly endorse the avoidance of aversive negative emotional and/or physiological states as the motivation for continued opioid use (source of reinforcement: reductions in negative states). The primary aim of this study was to explore whether this view is supported by the subjective effects of heroin reported by individuals with opioid use disorder (OUD). Methods: Responses during in-person interviews of participants to the question “What do you like about heroin?” were categorized as positive, negative, or mixed (positive and negative) reinforcement. In addition, we examined differences between these “reinforcement groups” in sociodemographic and clinical variables. Results: Participants (N = 307) with OUD were predominantly male (78.1%), with chronic heroin use (M = 15.8 years, SD=11.5), and 46.1% currently used heroin and were not enrolled in treatment. Agreement between two raters concerning the categorization of participant-reported effects of heroin into reinforcement categories was high, κ=0.924, p<.0005. Approximately half (49.8%) of participant-reported effects of heroin were categorized as attributable to positive reinforcement. About one-fourth (22.8%) were categorized as negative reinforcement and 9.0% as “mixed”. There were no statistically significant differences between the three reinforcement groups in any of the socio-demographic variables, duration of heroin use, or treatment status/interest. Conclusions: The results of this study indicate marked heterogeneity of heroin effects experienced by individuals with OUD and their source of reinforcement, respectively. Better integration of how individuals construe their drug use is important to understand the psychological—and neurobiological—processes in the development and maintenance of OUD.