OBJECTIVES: Acute coronary syndromes (ACS) consist mainly of ST-segment elevation myocardial infarction (STEMI) and unstable angina (UA)/non-STEMI (NSTEMI). ACS showed an enormous medical, social, and economic burden worldwide. ACS in the form of myocardial infarction is responsible for almost half of all deaths related to cardiovascular disease. South Korea compared to the OECD country average, shows high cardiovascular morbidity and mortality, and the recurrence rate is increasing every year. We examined the direct cost of hospitalization for ACS which planned percutaneous coronary intervention (PCI) using medical cost survey in South Korea. METHODS: We conducted a cost survey to examine the actual direct medical costs of the team of cardiologists, technicians of intervention and reimbursement reviewers in the hospital. To examine the cost data of a patients who received procedures, operations and admissions. We could select index patient cases through medical chart review as he/she had ever been visited the hospital since last 1 year. Through delphi panel discussion and reviewing, we refined the cost data excluding non-related ACS treatment in index case. RESULTS: It is the first survey of the actual cost in ACS. The total medical cost for ACS patients who have undergone the procedure was 4.451 million Korean won. The cost is lower level if considering difficulties in surgery. But among the components in ACS, the cost of stents and devices were largely accounted for the total cost. CONCLUSIONS: The medical cost of ACS in Korea is a burden to both patients and society, due to increasing recurrence in cardiovascular disease. Among the total cost, the cost of stents is higher than the inpatient cost. This is one of the reasons of the high medical cost in ACS. This result will have as implication the adjustment of the cost of stents and devices in ACS treatment in South Korea.