Japanese law provides for regular medical examinations for the aged. A simulation study to determine the relationship between medical expenditures of cardiovascular disease patients and government-sponsored health check-ups for the aged was conducted in a small community town in Kanagawa Prefecture. The results showed that medical expenditures decreased in accordance with an increase in health screening. However, medical expenditure for out-patients increased slightly with an increase in screening for those cardiovascular disease patients who had not received treatment prior to the government health checkup.