text: [EPIDEMIOLOGY OF OVER-ACTIVE BLADDER (OAB) SYNDROME].
  An over-active bladder is a common disorder which influences women's health and quality of life. There is difficulty defining the exact prevalence of the disorder since there are various definitions in the literature. The ICS definition from 2002 on the over-active bladder (OAB) syndrome enables more uniformity, by declaring that OAB syndrome is a symptomatic syndrome defined as presence of urgency with or without urinary incontinence, mostly accompanied by frequency and nocturia. In this article we reviewed the current medical literature on the prevalence of the OAB syndrome by focusing on relevant crosssectional and longitudinal studies, the trend changes during life, co-morbidities, the influence of quality of life and the economic burden following the disorder and its treatment. The authors' hope is that elevating awareness of the OAB syndrome will help improve its diagnosis and treatment.