OBJECTIVE: Urinary incontinence is an established complication of obesity in adult women. We examined the prevalence, severity, and impact of incontinence in obese compared to non-obese girls. METHODS: Subjects aged 12-17 years each completed a 29-item questionnaire assessing urinary symptoms and their impact. Clinically significant urinary incontinence was defined as involuntary urine leakage at least once weekly. RESULTS: 40 obese adolescent girls and 20 non-obese control girls were recruited. Among the obese girls, five (12.5%, 95% confidence interval: 4-28%) reported incontinence, and two of these five reported daily leakage. None of the 20 non-obese subjects reported leakage meeting the definition of incontinence. Incontinence severity scores (leakage frequency multiplied by leakage volume) averaged 1.3 in the obese group and 0.3 in the non-obese group (P=0.009) and were associated with symptom impact (P<0.001). Eleven (55%) of non-obese and 17 (43%) of obese subjects reported no urinary leakage, while infrequent, low-volume urine leakage was reported by 45% of both obese and non-obese subjects. CONCLUSIONS: Urinary incontinence affects more than 10% of obese adolescent girls. Frequency and volume of urine loss are directly related to the impact that incontinence has on the sufferer. Results highlight the importance of screening for symptoms of urinary incontinence in obese girls.