BackgroundIn Iran, people living with substance use disorders who engage in public drug use may be subjected to court-mandated treatment in compulsory drug detention and rehabilitation centers (CDDRC). This study aims to assess residential CDDRC's effectiveness in promoting sustained abstinence among people who use drugs (PWUD) in Kerman, Iran. MethodsBetween October 1, 2021, and September 30, 2022, 1,083 adult male PWUD with a diagnosis of substance use disorders and a history of engagement in public drug use were admitted to the CDDRC in Kerman. They were followed-up for 12 months after discharge. The relationship between baseline variables and abstinence, assessed using rapid urine tests, was examined using crude logistic regression models. ResultsMost PWUD were 30 or older (n = 876, 80.9 %) and had a history of previous CDDRC admission (n = 638, 58.9 %). At the end of the 12-month follow-up, only 2.6 % (95 % confidence intervals: 1.7–3.7) were abstinent. Individuals with limited education (Odds ratio [OR] = 3.43; 1.50–7.95) and those with a prior history of admission to the CDDRC (OR = 3.73; 1.55–9.89) had increased odds of relapse. ConclusionsThe effectiveness of CDDRC in promoting abstinence among the participants was minimal. This highlights the necessity of reassessing support and investment in these interventions and considering more evidence-informed alternative approaches in Iran.