Aim: To investigate perioperative opioid usage in patients on methadone or buprenorphine as medication assisted treatment for opioid use disorder (MOUD) that attended a transitional pain clinic (Personalized Pain Program, PPP). Methods: In this retrospective cohort study, data was abstracted from the electronic medical record of adults on MOUD with surgery and attendance at the PPP between 2017-2022. Daily non-MOUD opioid use over 5 time-points was evaluated with regression models controlling for differences in days since surgery. Time to complete non-MOUD opioid taper at the last PPP visit was analyzed by accelerated failure time and Kaplan-Meier models. Results: Fifty patients (28 on methadone, 22 on buprenorphine) were included with median age of 44.3years, 54% male, 62% Caucasian, and 54% unemployed. Methadone inpatient administration occurred in 92.8% but only 36.3% of buprenorphine patients. Non-MOUD opioid use decreased over time (β=-0.54, p<0.001) by a median of 90mg morphine equivalents (MME) during PPP with 46% tapered off by the last visit. Older age, employment status, duration in PPP, and extremity surgery were associated with lower MME while mental health conditions, longer hospital stay, and higher discharge opioid prescriptions were unfavorable. The average time to non-MOUD opioid taper was 1.79x longer in buprenorphine patients (p=0.026), 2.75x in males (p=0.023), 4.66x with a mental health condition (p<0.001), 2.37x with chronic pain (p=0.031), and 3.51x if non-MOUD opioids were prescribed pre-admission, however, higher initial MOUD level decreased time to taper (p=0.001). Conclusion: Postoperative opioid tapering utilizing a transitional pain service is possible in patients on MOUD.