© 2019, Pacini Editore S.p.A.. All rights reserved.Background: Probation is a well-intentioned approach that aims to bring substance abusers back into the community. In the literature there is a lack of studies dedicated to showing how probation affects the treatment outcomes of opioid use disorders. Aim: This study aims to explore the probation’s impact on treatment outcomes of opioid use disorders by comparing the early remission rates of patients admitted voluntarily and by probation. Methods: 158 convicts on probation and 303 patients with opioid use disorder who applied voluntarily were included in the study. The sociodemographic characteristics and the early remission rates of the patients were compared. Based on DSM-5 criteria, early remission refers to the failure to meet any of the criteria of substance use disorder, other than craving or a strong desire, and the compulsion to use such substances for at least 3 months, but for a time period shorter than 12 months. Results: Early remission rate among patients who applied voluntarily (38.9%) was significantly higher than patients who were referred to us as convicts on probation (26.6%). Independent factors raising the probability of early remission were found to be voluntary referral to outpatient clinics (1.791-fold), being male (4.855-fold) and old age (1.090-fold), while being single (0.508-fold) and a long duration of substance use (0.981-fold) were found to be independent factors lowering the probability of early remission. Conclusion: The findings of the present study demonstrate that in patients suffering from opioid use disorder, the willingness and motivation of the individual to undergo treatment were more effective than motivations based on the threat of legal sanctions.