OBJECTIVE: To document prevalence of mild, moderate, and severe urinary incontinence among ethnically diverse perimenopausal women, identify risk factors, and assess the effect of severity on women’s daily lives using treatment seeking, bother, and nighttime voiding as indicators. METHODS: Baseline data from the longitudinal cohort of the Study of Women’s Health Across the Nation, a prospective, multiethnic, multisite study of the natural history of menopausal transition was used (n = 3302). Interview and self-completed questionnaires assessed most variables of interest. Body mass index and diabetes mellitus were measured clinically. Incontinence severity was derived by multiplying frequency by volume leaked. Risk factors and effect on treatment seeking, bother, and nighttime voiding were assessed by the construction of multiple logistic regression models for each ethnic group and the total population. RESULTS: Mean age was 46.4 years. Incontinence prevalence was 57%, with nearly 15% categorized as moderate and 10% as severe. Biologic factors constituted the most important risk for severity, specifically perimenopausal compared with premenepausal status (odds ratio [OR] 1.35), body mass index (OR 1.04), diabetes mellitus (OR 1.55), and current smoking (OR 1.38). Nonwhite groups had lower risk, but the relationship of ethnicity is complex. Severity was associated with likelihood of discussing with a health care provider, with bothersomeness, and with likelihood of nighttime voiding. CONCLUSION: Large numbers of perimenopausal women experience urinary incontinence with 25% wearing protection or changing undergarments on several days per week. Mutable factors predicting severity included body mass index and current smoking.