OBJECTIVE: We compared the direct health care costs for patients receiving different prescription pharmacologic agents for overactive bladder (OAB) symptoms in a managed care setting. METHODS: We used administrative medical and pharmacy claims data from >30 managed care plans. Patients newly diagnosed with OAB who initiated treatment with tolterodine extended release (TOL ER), oxybutynin extended release (OXY ER), or oxybutynin immediate release (OXY IR) were followed for 12 months from the date of initial diagnosis. Patients were required to be continuously eligible for pharmacy and medical benefits during the study period. Total mean medical costs were assessed for the 12-month follow-up period and were compared across the treatment groups after statistical adjustment for age, sex, and days to treatment initiation. Medical costs were calculated from inpatient admissions, emergency room visits, outpatient physician visits, other prescription drugs, and diagnostic/laboratory services. RESULTS: A total of 6110 patients initiated treatment with TOL ER (mean age 55y, 77% women), 3325 with OXY ER (mean age 55y, 73% women), and 893 with OXY IR (mean age 57y, 61% women). Patients who received OXY ER ($9,063) and OXY IR ($10,523) had significantly higher adjusted annual mean medical costs than did patients who received TOL ER ($8,073, p=0.0175 and p=0.0001, respectively). CONCLUSIONS: Diagnosing and managing patients with OAB is challenging, especially as it relates to pharmacologic treatment. Observed lower medical costs of TOL ER patients in this study may have broad implications. Results from this study warrant further analysis that fully incorporates adjustments for the factors associated with treatment selection as well as disease-specific drivers of health care costs.