The aim. Estimation of ST2 plasma level in patients with acute myocardial infarction without ST elevation (NSTEMI) and its relationship with different clinical characteristics.Materials and methods. 165 patients aged from 35 to 79 (average of 60.7±0.8 years) with various forms of coronary artery disease (CAD) with and without arterial hypertension were examined. The variability of plasma ST2 level in different forms of CAD and in NSTEMI group was analyzed depending on gender-age and clinical characteristics and features of the disease course.Results:The results of the present investigation were that the ST2 level in the main cohort was in range from 5.5 to 233.9 (in the middle – 49.8±3.5 ng / ml (median indicator – 34.7 and the interquartile range – 21.9 and 59.1 respectively).Significantly higher ST2 levels were found in patients with NSTEMI, unlike the comparison group, in the median analysis (35.9 vs. 27.7 ng/ml, p=0.047) and no statistical differences were observed in the mean values.In patients with NSTEMI, a certain association of ST2 level in plasma with the MI course was detected. A higher level of neurohormone is registered with anterior unlike posterior ECG localization of MI; at high unlike moderate risk on the GRACE scale; when complicated unlike the uncomplicated course of MI; in the case of acute HF and cardiac arrhythmias unlike patients with the absence of these manifestations in the acute period of MI. Conclusions. High variability of ST2 level in plasma was demonstrated in patients with NSTEMI on the first day after destabilization (minimum and maximum values – 12.7 and 233.9 respectively, median – 35.9 and interquartile range – 25.9 and 55.7 ng / ml).It is shown that significantly higher ST2 level in plasma is determined in patients with acute MI regardless of its variant among different clinical forms of CAD.It is found that significantly higher level of ST2 in patients with NSTEMI is recorded in the case of concomitant HTN and type 2 diabetes, with smoking and heavy cardiovascular heredity. Proved influence of the character of MI course on the level of ST2 in plasma, significantly higher level of neurohormone was determined with anterior localization of MI, high risk on the GRACE scale (≥ 140 points), complicated course of MI, development of cardiac arrhythmias and HF in the acute period of MI.