Research on treatment utilization among offenders with mental health problems and substance use problems, i.e. the 'triply troubled', is scarce. The aim was to contribute to the general knowledge about treatment patterns among the triply troubled. This register-based study explored treatment patterns during a 3-year follow-up among 157 Swedish offenders with substance use problems who had undergone forensic psychiatric assessment. There were three subgroups of treatment users: low treatment, planned substance abuse treatment and substance abuse emergency room visits, and planned psychiatric treatment. About 40% of the participants displayed a stable treatment pattern. Outcomes were less successful for those participants displaying a non-stable treatment pattern. Allocation of treatment resources should take into account the associations between treatment patterns and recidivism into criminality. Also, it should be valuable for clinicians to gather information on treatment history in order to meet various treatment needs.