To compare the characteristics of and baseline factors associated with prevalent and incident urinary incontinence in a diverse cohort of midlife women, the authors analyzed the baseline and first five annual follow-up visits of the Study of Women's Health Across the Nation (SWAN), 1995-2001. From responses to annual questionnaires, the authors defined prevalent incontinence as at least monthly incontinence reported at baseline and incident incontinence as at least monthly incontinence first reported over follow-up. They used multiple logistic regression for their comparison. The mean age of their cohort at baseline was 45.8 (standard deviation: 2.7) years. Prevalent incontinence was 46.7%, and the average incidence was 11.1% per year. Most women reported stress, but a higher proportion developed urge incontinence (15.9% vs. 7.6% at baseline). African Americans (29.5%) and Hispanics (27.5%) had the lowest prevalence of incontinence; African Americans (11.6%) and Caucasians (13.4%) had the highest average annual incidence. Parity, diabetes, fibroids, and poor social support were associated with prevalent incontinence, while high body mass index, high symptom sensitivity, and poor health were associated with incident incontinence. In midlife women, incident incontinence is mild with different characteristics and baseline risk factors; overweight women have a higher risk of developing incontinence.