Abstract. The role of aldosterone and galectin-3 in the development of fibrotic processes in the heart and kidneys in cardiorenal syndrome that developed against the background of chronic heart failure (CHF). In all three groups of patients under observation, a statistically significant increase (r˂0.05) was found, compared with the reference values of the concentration of galectin -3. Along with this, a statistically significant increase in aldosterone concentration was found in patients of the main group compared to the control group (r<0.001). Also, there was a significant increase in its concentration in patients with low and intermediate ejection fraction of CHF. Thus, in patients with CHF with intermediate and low ejection fraction of the left ventricle, significantly increased concentrations of galecten-3 and aldosterone, indicating the processes of myocardial fibrosis, and their correlation with the severity of the disease, were established.