Background: Drug eluting stent has been used in a clinical practice since this year. However, its MACE(major cardiac adverse event) including acute or subacute thrombosis in every day practice has not been evaluated fully. We sought to evaluate in-hospital and 30 day events who had implanted Cypher stent (Cordis Co. USA). Methods: From March to July 2003, 70 patients (mean ages, 60 짹 10 years [range, 39-79], 55 male) who had implanted single or multiple Cypher stents were enrolled. Clinical diagnosis included acute myocardial infarction in 16 patients, stable angina 27 and unstable angina in 27 patients. Treated arteries included LAD 48, LCx 12, RCA 7 and left main coronary in 3 patients. Risk factors included diabetus mellitus in 25, hypertension in 26, smoking in 20 and hypercholesterolemia in 9 patients. Results: There was 2 MACE in our clinical settings. One successfully implanted patient had thrombotic occlusion of stented site at day 6 after discharge. This patient omitted loading dose of clopidogrel. Another 70 year old female died suddenly during the sub-ICU care after 4 days of multiple stents insertion. There was no further 30 day event. Conclusions: Acute or subacute MACE including thrombotic occlusion need to be further monitored.