Opioid use in chronic non cancer pain (CNCP) is still controversial regarding their effectiveness and safety. We conducted a 2-year prospective cohort study in 4 multidisciplinary chronic pain clinics to assess long-term opioid effectiveness in CNCP patients. All adult CNCP patients consecutively admitted to their first consultation were recruited. Demographic and clinical data were collected, and propensity score matching was used to adjust for differences between opioid users and nonusers. The Brief Pain Inventory and the Short version of Treatment Outcomes in Pain Survey were used to measure pain outcomes and quality of life. A total of 529 subjects were matched and included in our analysis. Rate of prescription opioid use was 59.7% at baseline, which increased to 70.3% over 2 years, of which 42.7% of the prescriptions were for strong opioids. Opioid users reported no improvement regarding pain symptoms, physical function, emotional function, and social/familiar disability. Opioid users reported higher satisfaction with care and outcomes at 1 year of follow-up, but at 2 years, they only reported improvement in satisfaction with outcomes. Opioids have shown limited effectiveness in long-term CNCP management, as opioid users presented no improvements regarding functional outcomes and quality of life. These findings emphasize the need for proper selection and outcome assessment of CNCP patients prescribed opioids. PERSPECTIVE: This study adds important additional evidence concerning the controversial use of opioids in CNCP management. Opioid users presented no improvement regarding pain relief, functional outcomes and quality of life over 2 years of follow-up. Therefore, our results support and highlight the limited effectiveness of opioids in long-term CNCP management.