OBJECTIVES: The purpose of this study is to estimate the cost of ischemic stroke after its diagnosis and compare to its consecutive monthly costs for 1 year. METHODS: The study subjects were patients with an initial diagnosis (ICD code: I63). The data were obtained from National Health Insurance Corporation data, National health and nutrition examination survey and national statistics. We analyzed costs in societal perspective. Stroke costs are classified into direct medical costs, transportation and caregiver costs. RESULTS: Ischemic stroke costs for the initial month were ten times as much as the costs for the following successive month after diagnosis. In the first month, medical costs accounted for almost 90% of the total stroke costs. Inpatient costs and outpatient costs are occupied 55%, 33% respectively. CONCLUSIONS: The stroke costs after initial diagnosis are substantial. The effort to reduce stroke costs and early detection for stroke can reduce the burden to society.