Both communities were screened for morbidity and case-fatality rates for coronary heart disease and stroke. Morbidity and mortality data were obtained from seven area hospitals and the State Health Departments of Rhode Island and Massachusetts. Outcome criteria were developed collaboratively by the Pawtucket Heart Health Program, the Stanford Five-City Multifactor Risk Reduction Study, and the Minnesota Heart Health Program, to maximize the scientific value of the conclusions drawn from the three studies and to allow pooling of final data. Surveillance was complete for 1980 to 1983 and continued through 1993.