Although congestive heart failure is a fairly common clinical syndrome and the societal costs associated with its care are high, relatively little is known about the incidence or prevalence of the condition in the community. Using the resources of the Rochester Epidemiology Project, we identified all 46 persons 0 through 74 years of age who had a new diagnosis of congestive heart failure during 1981 and all 113 persons with a prevalent diagnosis on Jan. 1, 1982, in the city of Rochester, Minnesota. After confirming the diagnosis in the medical record by using criteria similar to those in the Framingham study, we found the annual incidence of congestive heart failure to be 110 per 100,000 after adjusting for age. Incidence rates were higher among male than among female study subjects (157 versus 71 per 100,000). In both male and female subjects, the incidence generally increased with advancing age, reaching 1,618 per 100,000 and 981 per 100,000, respectively. Prevalence rates on Jan. 1, 1982, demonstrated similar patterns. Overall, the prevalence of congestive heart failure was higher among male than among female subjects (327 versus 214 per 100,000) and increased exponentially with advancing age, reaching almost 3% in both sexes. Survival after a diagnosis of congestive heart failure was extremely poor, with only 80% alive at 3 months and 66% at 1 year. These data underscore the effect of congestive heart failure in the community and provide estimates of the number of persons who might benefit from early intervention.