OBJECTIVE The objective of this monitoring was to evaluate persistence in the treatment of patients with overactive bladder syndrome (OAB) using mirabegron. DESIGN Prospective clinical study. SETTING 10 gynecological and urological departments in CZE. MATERIALS AND METHODS This is an analysis of a prospective, multicenter monitoring which started in May 2014 and will continue for 1 year. This monitoring included patients 18 years old who have had symptoms of OAB for minimum 3 months. The patient check-up was performed 6 months (±2 weeks) after the first visit. The dosage of mirabegron was 50 mg per day. For the evaluation the treatment efficacy we employed the TS-VAS and PPBC. During the check-up it was ascertained how many patients discontinued the treatment with mirabegron, and reasons for this interruption were established. The statistics were calculated using the software SPSS 20.0. RESULTS A prospective monitoring was performed on 206 patients. Their mean age was 62.8 years (range 23-89); mean body mass index for the whole group of patients was 27.3. At the check-up 6 months post-initiation of treatment it emerged that 55/206 (27%) patiens had discontinued the treatment. The reasons for discontinuation of treatment were: 24/55 (43%) insufficient treatment efficacy, 29/55 (53%) other reasons (the main reasons here were hospitalisation, surgery, gravidity) and 2/55 discontinued therapy because of side effects. The side effects were tachycardia, eye irritation, lower abdominal pain and vasculitis, and they were mild in nature. The termination of the study was 7/28 (25%) in the group of patients without previous treatment before mirabegron. Discontinuation of the treatment in the group of patients with previous anticholinergic treatment was 48/178 (27%). At the evaluation of the efficacy of the treatment during the check-up 6 months after initiation of treatment the mean TS-VAS was 77.5, a decrease of the scale of bothers evaluated by PPBC before treatment from a mean value of 3.56 to a value of 1.77. CONCLUSIONS Our hypothesis, that persistence in treat-ment with mirabegron would be relatively high due to reduced side effects and better cure effect, was confirmed, and this is the reason for higher rates of persistence in the treatment at 6 months check-up (73%).