Urinary incontinence is associated with decreased female sexual function, but little is known about the prevalence, predictors, and impact of urine leakage during sexual activity among women in the community. The purpose of this study was to evaluate the prevalence and impact of urine leakage during sex in ethnically diverse, community-dwelling midlife and older women. Urinary incontinence and sexual function were assessed by structured questionnaire in a multiethnic, community-based cohort of women enrolled in Kaiser Permanente Northern California, an integrated healthcare delivery system in California. All women were aged 40-80 years and sampled from 1 of 4 racial/ethnic groups (20% black, 20% Latina, 20% Asian, and 40% non-Latina white). Differences in frequency, bother, and fear of urine leakage during sexual activity were examined among women with monthly, weekly, and daily urinary incontinence and across different types of urinary incontinence (stress, urgency, mixed, and other type urinary incontinence), with the use of chi-square tests. Independent risk factors for urine leakage during sexual activity were identified through multivariable logistic regression. Of the 509 women who reported being sexually active and having at least monthly urinary incontinence, 127 of them (25%) reported experiencing any urine leakage during sex during the past 3 months. Nineteen percent of the women reported being subjectively bothered by leakage during sex, and 16% of them reported restricting sexual activity because of fear of leakage. Women with more frequent underlying urinary incontinence were more likely to report experiencing or being bothered by leakage during sex and restricting sexual activity because of fear of leakage (P<.001 for all). Participants with predominantly stress or mixed type urinary incontinence were more likely to report experiencing leakage during sex and being subjectively bothered by this leakage (P<.002 for all). Factors independently associated with leakage during sex were depression (odds ratio,1.96; 95% confidence interval, 1.20-3.20), symptomatic pelvic organ prolapse (odds ratio, 2.10; 95% confidence interval, 1.11-3.98), mixed vs urgency type urinary incontinence (odds ratio, 3.16; 95% confidence interval, 1.70-5.88), stress vs urgency type urinary incontinence (odds ratio, 1.94; 95% confidence interval, 1.01-3.70), and frequency of sexual activity (odds ratio, 1.6395% confidence interval, 1.05-2.55), but not age or race/ethnicity. Up to a quarter of women with at least monthly urinary incontinence in the community may experience urine leakage during sexual activity. Many incontinent women who leak urine during sex remain sexually active, which indicates that the preservation of sexual function should still be a priority in this population. Among incontinent women, depression, pelvic organ prolapse, and stress mixed-type urinary incontinence may be associated with urine leakage during sexual activity.