The aim of this study is to assess the feasibility of introducing clinical case management into a youth alcohol and other drug treatment setting. Case management as usual (CMAU), the current brokerage model operating as a control group was compared to clinical case management (CCM). Individual client outcomes were compared with the site as the grouping variable. Although alcohol and drug outcomes were similar, arguably slightly favouring the intervention group, results suggest that young people receiving clinical case management showed potentially greater improvement across a range of other health outcomes including mental health, treatment utilisation and social outcomes than the CMAU brokerage model. The study examined the feasibility of training clinicians in a youth alcohol and drug treatment agency in a clinical case management model and examined whether this more intensive case management approach could improve substance use and mental health outcomes for young people. Although widely used, much less is known about the efficacy of case management within substance use treatment settings, where case management tends to be loosely defined and encompasses a broad range of activities. The originality of this study is that little is known about the effectiveness of case management in youth services, where it tends to be the primary service offered.