Opioid agonist treatment (OAT) is an effective treatment for opioid use disorder (OUD) as it prevents withdrawal symptoms, reduces cravings, and has been associated with beneficial outcomes such as reductions in illicit drug use and related harms (e.g., overdose, mortality, etc.). To better understand OAT-related experiences and release-related perspectives among federal offenders with OUD, we conducted the current longitudinal mixed-methods study. Please note that this report is a one page summary. If you wish to have a copy of the full report, please send a request comment via the Open Government Portal or email the OG team: opengovernmentgen-nhq@csc-scc.gc.ca.