This paper examines or current state of knowledge of the epidemiology of urinary incontinence. The population studied was community-dwelling non-institutionalized persons. The review includes discussion of the prevalence, incidence, natural history and presence of racial and ethnic differences in the epidemiology of urinary incontinence. We also review correlates and potential risk factors that have been revealed in epidemiological studies. Differences between epidemiological and clinical approaches to a health problem, help-seeking behavior and methodological issues for research are also discussed. We have reviewed a large number of completed studies in the field of urinary incontinence, and have emphasized high-quality and population-based studies. We also wished to present studies from a variety of countries. Because of the abundance of studies, only a small fraction can be presented here. Other studies may have equal standards and useful information, but lack of space precludes their inclusion.