Background : In case of acute myocardial infarction, angiogenic activity is changed according to the change of various pro- and anti-angiogenic factors. Blood levels of several vascular growth factors in patients with acute coronary syndrome are reported but information about angiogenic activity at initial phase of myocardial infarction is unknown. The aim of this study was to assess the early change of angiogenic activity in association with angiopoietins at initial phase of ST elevation myocardial infarction(STEMI). Method and Results : Blood angiopoietin-1(Ang-1) and angiopoietin-2 (Ang-2) levels were measured just before primary percutaneous coronary intervention(PCI) in 45 patients with ST elevation myocardial infarction. Blood levels were compared with those of 15 patients with unstable angina(UA) who were undergone emergency PCI and 20 controls with normal coronary angiography. Patients with STEMI had significantly lower Ang-1 blood levels compared with UA patients and controls (p<0.001). There were no differences in Ang-1 levels between UA patients and controls ( p=0.255 ). Ang-2 levels were not different between groups ( p = 0.216 ). Conclusion : Blood Ang-1, one of predominant coordinators of angiogenesis, levels were decreased at initial phase of STEMI. These findings reflect that change of angiogenic activity begins at initial phase of myocardial infarction.