OBJECTIVES: To compare persistence and adherence with mirabegron versus antimuscarinic treatment for overactive bladder (OAB).  METHODS: This was an exploratory analysis of retrospective claims data from the largest Private Drug Plan database in Canada. Patients aged ≥18y who had a first prescription claim for a target medication during a four-month index period in 2013 were identified. A six-month look-back was used to categorize patients as ‘treatment-naïve’ (no claims for OAB medication) or ‘treatment-experienced’ (≥1 prior medication) during this time. Time to end of persistence (defined by a maximum gap in therapy of 30 days or switching to another medication) and adherence (calculated by medication possession ratio) were analyzed after six months. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated for mirabegron versus each antimuscarinic, using Cox proportional hazards modeling. RESULTS: Data were analyzed for 13,391 patients (mirabegron, n=993). In the treatment-experienced cohort, six-month persistence was highest with mirabegron (51%), followed by solifenacin (39%) (HR 1.383; CI: 1.109−1.726; p=0.004), ranging to 18% with oxybutynin IR (HR 2.488; CI: 1.961−3.157; p<0.001). In the treatment-naïve cohort, persistence was also highest with mirabegron (40%), followed by fesoterodine (24%) (HR 1.512; CI: 1.333−1.716; p<0.001), ranging to 13% with oxybutynin IR (HR 2.315; CI: 2.093−2.561; p<0.001). Median number of days on therapy with mirabegron was 183 (treatment-experienced) and 129 (treatment-naïve), compared with 67−120 and 34−90 days with antimuscarinics, respectively. Mean adherence overall was 68% with mirabegron vs 39−55% with antimuscarinics (each p<0.05 vs mirabegron).  CONCLUSIONS: Patients treated with mirabegron had improved persistence and adherence over antimuscarinics. While differences in patient characteristics among the OAB drugs were accounted for within the model, results should be viewed in the light of the likely characteristics of patients started on any new medication to the market; hence this sample may not be reflective of more mature usage.