Objective: To assess the impact on sexual function attributed to lower urinary tract dysfunction in a female obese population. Design: We performed a case-control study based on the registry of a university hospital obesity unit. A consecutive sample of women with body mass index(BMI) X30 (obese) was randomly matched by age, gender and residential county to control subjects using the computerized Register of the Total Population. Data were collected by a self-reported postal survey including the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12). Results: The questionnaire was completed and returned by 279/446 patients (62%) and 430/892 control subjects (48%). Obese women reported significantly lesser satisfaction with their sexual life, more frequent symptoms of urinary incontinence at intercourse, more often fear of urine leakage at intercourse, a higher tendency toward avoiding intercourse and more frequent feelings of guilt and disgust during intercourse (Po0.001). While considering sexual function in a subset of women with urge or stress urinary incontinence, the overall PISQ-12 scores were significantly lower in obese women compared to their age-matched nonobese controls for both the conditions (Po0.001). In an adjusted multivariate analysis, a BMI 430 was independently associated with a significantly increased risk for sexual dysfunction (odds ratio (OR) 1.8; 95% confidence interval (CI) 1.1-2.9), as were symptoms of urge or stress urinary incontinence (OR, 2.0; 95% CI, 1.3-3.1 and OR, 2.6; 95% CI, 1.7-4.0), respectively. Conclusion: Urge and stress urinary incontinences are more common and have greater impact on sexual function in obese women.