Introduction. CHF is a complex disease that is based on a number of pathogenetic processes that induce the formation of different compounds during its development. These compounds can be defined as biomarkers. The growing interest in analyzing the relationship between sST2 and the prognosis of chronic heart failure can be justified by several aspects. First of all, sST2 concentration is increased by a variety of risk factors for this condition, including coronary heart disease, hypertension, type 2 diabetes, obesity, and others. The aim is to study the level of sST2 biomarker in patients with chronic heart failure. Materials and Methods. The research project involved 120 patients struggling with chronic heart failure. These participants were distributed among cardiology departments housed within the structure of the Voronezh Regional Clinical Hospital No. 1. Demographically, women occupied the majority - 62.5% (75 out of 120 participants), while men accounted for 37.5% (45 out of 120 participants). The study was divided into two phases. The first consisted of obtaining consent from the patients, collecting anamnesis and performing the necessary laboratory and instrumental investigations (including ECG and echocardiography). The second phase investigated changes in the clinical picture of CCN over one year. Results. The mean value of sST2 reached 32.15 ng/mL in the study group. In most cases, patients categorized as functional class I had a stable course of the disease without obvious signs of deterioration. However, in the group with functional class II, the data indicated an equal distribution between patients with a stable condition and those who experienced decompensation phases. In contrast, patients with functional class III were more likely to experience decompensation, indicating an exacerbation of chronic heart failure during the following year. For patients classified as functional class IV, stable disease course was not recorded at all. Discussion. The observed sST2 levels are consistent with the data from scientific publications. Conclusions. The level of sST2 in this subgroup was found to be higher than the reference values for the general population. Analysis of sST2 and NT-proBNP revealed their correlation with other indices indicating the progression of CCN. This allows us to conclude about the pathogenetic role of these biomarkers in the development of various pathologic processes leading to deterioration of CHF. Increase of sST2 is associated with aggravation of the disease course.