canada’s first nations population experiences elevated rates of opioid use and negative opioid-related consequences. these rates stem from the long history of colonization that first nations populations have faced, which has resulted in unique treatment access barriers and a need for culturally and contextually relevant treatment. the purpose of this study was to longitudinally evaluate the first on-reserve methadone maintenance therapy program in canada through both client questionnaires and staff interviews. forty-nine clients (mean age of 40, 51% female, 100% first nations identification) and 11 staff members of the program participated in this study. overall, clients noted self-improvement; improved quality of life, housing condition, employment status, and family support; and decreases in symptoms of anxiety and depression, overall psychological and physical distress, and drug use and high-risk behaviours. qualitatively, clients spoke positively of the treatment centre and noted challenges of the program. staff noted their primary goal as seeing clients become substance free and they also spoke about the importance of the community’s support of the program. staff noted challenges with funding and reported a desire to see the program continue to help the community until everyone is healed. overall, the results of the evaluation were positive and show that the program is succeeding in the eyes of the clients and the staff.