Purpose-Problematic substance use is associated with adverse outcomes that extend beyond the individual, resulting in significant cost to the community through health care, criminal justice and other psychosocial factors, including child protection and family support. These factors create concerns for treatment services, with an increasing demand for cost-effective solutions to this problem. This paper seeks to address these issues. Design/methodology/approach-This prospective cohort study examined the effect of client variables on retention within a short-term (56 days) modified therapeutic community (MTC) in the Australian Capital Territory. A total of 28 residents (17 males, 11 females) took part in the study, which included quantitative and qualitative measures. Findings-Results demonstrate a trend in favour of dynamic client variables as effective predictors of retention, with substance use severity being a significant predictor (p ¼ 0.023, d ¼ 0.91). Content analysis demonstrates that those with severe substance use have more intentions to engage in aftercare. Originality/value-Short term treatments are seen as providing a gateway to further treatment, especially for chronic substance-using clients.