OBJECTIVES: To carry out a cost and consequences analysis (CCA) of treating Overactive Bladder (OAB) with two flexible-dose of Fesoterodine in routine medical practice in Spain, from the perspective of the Spanish National Health System (NHS). METHODS: The CCA was populated with data from an observational, retrospective and multicenter study including OAB patients, both genders, aged 18+ years-old managed under routine medical practice conditions of care. OAB patients initiating flexible-dose of Fesoterodine were included in two groups according with the flexible posology prescribed: escalating from 4-to-8mg (escalating group) or initiating and maintaining 8mg (maintaining group). Consequences included a health outcomes profile from the patient perspective and the clinician judgment. Costs were estimated from healthcare resources utilization only and used year 2015 unitary prices.  The patient outcomes measures included symptoms severity and specific quality-of-life by using the OAB-q questionnaire, Patient Perception Bladder Condition (PPBC), Patient Perception Urgency Scale (PPUS), and Treatment Benefit Scale (TBS). Clinician judgment was approached by the Clinical Global Impression (CGI) scale. General linear models, logistic and ordinal regression adjusting by covariates were applied.  RESULTS: A total of 350 (156 in maintaining group and 194 in escalating) symptomatic OAB patients were extracted from the study to populate the CCA. Adjusted healthcare total costs were not statistically different; €50.6 (CI:157.4-55.1), p=0.361. However, patient-reported-outcomes were significantly better in the maintaining group than in the escalating; OAB-q symptoms (22.6 vs. 26.8, p=0.015), HRQoL (74.5 vs. 71.1, p=0.053), less patients with urinary incontinence (29.5% vs. 46.4%, OR= 0.4 (CI:0.3-0.7), p=0.001, and better perception or urgency OR= 1.8 (CI:1.2-2.8), p=0.008.   CONCLUSIONS: Despite the study design, this cost-consequences analysis found that initiating 8mg dose of fesoterodine was associated with similar healthcare costs but better patient outcomes than escalating from 4mg in the treatment of Overactive Bladder in routine medical practice.