objectives: This study was conducted to estimate medical expenditure attributable to overweight and obesity in adults with ischemic heart disease and stroke using Korea National Health and Nutrition Examination survey data and Korea National Health Corporation data. methods : The medical expenditure of ischemic heart disease and stroke related to overweight and obesity were composed of inpatient care costs, outpatient care costs and medication costs. The population attributable risk (PAR) of overweight and obesity was calculated from national representative data of Korea such as the National Health Insurance Corporation cohort data and 2005 Korea National Health and Nutrition Examination survey data. results: The medical expenditure attributable to overweight and obesity of ischemic heart disease were 97.4 billion won(74.1-122 billion won). and stroke were 64.6 billion won(33.1-98.1 billion won). Consequently, these costs corresponded to 11.4% of total medical expenditure due to ischemic heart disease and stroke. conclusion: We conclude that overweight and obesity have increased medical expenditure from ischemic heart disease and stroke in Korea. These findings provide important support for implementing overweight and obesity management strategies in Korea.