The aim: To determine the diagnostic value of serum levels of ST2 in patients with the acute coronary syndrome (ACS) and its correlation with NT-proBNP levels. Materials and methods: NT-proBNP and ST2 concentration in serum of patients was measured on admission to the hospital and on the 10th day of the treatment using NT-proBNP ELISA (Biomedica, Slovakia) and Presage ST2 assay (Critical Diagnostics, USA), respectively. Results: Statistically significant direct correlations (p<0.05). The simultaneous increase of ST2 and NT-proBNP serum levels above their threshold in patients with ACSelST (sensitivity – 92.5 %, specificity – 74.2 %, AUC – 0.893, р<0.05) indicated a significant risk of cardiovascular (CV) complications of acute myocardial infarction (AMI) during the inpatient period, e.g. acute heart failure, acute LV aneurysm, recurrent AMI, as well as rhythm and conductivity disturbances. Conclusions: The data suggest that both ST2 and NT-proBNP may prove useful in predicting unfavorable prognosis during the inpatient care of AMI, as the simultaneous increase of these biomarkers above their threshold values indicates a significant risk of CV complications.