The Ontario Health Survey was conducted in 1990 by the Ontario Ministry of Health to assess the health status of the province's population. Self reports of health status and problems, treatment, and risk factor profiles were collected by interviewer and self-completed questionnaires. The present report addresses the prevalence and distribution patterns of cardiovascular disease and selected risk factors and is based on data from 44,000 residents of Ontario aged 18 years and older. Data collected from the survey demonstrate that the incidence of circulatory disease was 3% and heart disease was 4% in the population of Ontario. As well, the prevalence rates for selected cardiovascular risk factors were: high blood pressure (10%), diabetes (3%), smoking (31%), obesity (25%), and inactivity (72%) and are reported as a function of age category and sex. These findings are compared with the prevalence of risk factors in other regions of Canada. This information provides a basis for the development, implementation, and evaluation of comprehensive programs that are aimed at reducing cardiovascular risk factors and mortality and morbidity from cardiovascular disease.