Background: Given the risk of opioid misuse among chronic pain patients being treated with longterm opioid pharmacotherapy, non-pharmacological treatments are needed. Further, in light of hedonic deficits in this population, therapies that enhance positive affect may be useful. The purpose of this study was to examine effects of a Mindfulness-Oriented Recovery Enhancement (MORE) intervention on ecological momentary assessments (EMA) of pain and positive affective experience, and to determine if changes in pain, affect, and their interaction were associated with opioid misuse at post-treatment. Methods: This study examined unpublished EMA data from a subset of participants (N = 55) in a previously published RCT (NCT01505101) of MORE versus a support group (SG) control. Across 8 weeks of treatment, patients completed up to 224 EMA measures of pain and affect. Multilevel models and generalized estimating equations examined effects of treatment on momentary pain and positive affect, and generalized linear models examined associations between pain and affect and changes in opioid misuse by post-treatment. Results: Patients in MORE reported significantly greater improvements in momentary pain (p = 0.01) and positive affect (p = 0.004) than patients in the SG. Further, over the entire course of treatment, patients in MORE were significantly more likely to exhibit positive affect regulation (OR= 2.75) than patients in the SG. Finally, improvements in positive affect (but not pain) over the course of intervention were associated with reduced risk of misusing opioids by post-treatment (p= 0.02). Conclusion: MORE may be a useful non-pharmacological treatment for pain and hedonic deficits among chronic pain patients at risk for opioid misuse. (C) 2017 The Authors. Published by Elsevier Ireland Ltd.