Urinary incontinence (UI) is recognized as a significant problem in adult females with cystic fibrosis and can often have a marked impact on day-to-day activities. The prevalence and severity of UI in the pediatric cystic fibrosis (CF) female population is less clear and there are no comparative data with healthy children or children with other respiratory disorders. An anonymous self-completed semi-structured questionnaire was used to study the prevalence rates of UI in girls with CF aged between 11 and 17 and compared it to age-matched asthmatic and healthy girls. The prevalence of UI in girls with CF was significantly higher (17/51, 33%) than the asthmatic (4/25, 16%) and healthy girls (2/27, 7%) (P = 0.02). It may manifest as early as 11 years of age and is associated with increasing lung disease. Surprisingly it is perceived as a relatively minor problem in terms of the distress it causes. Pediatric CF clinics should be routinely addressing UI as a potential problem in all girls from the age of 11 years.