Abstract Background and Aims To study the functional state of the kidneys and cardiorenal relationships in patients with chronic heart failure, depending on the representation of components of metabolic syndrome Method To achieve the objectives, 227 male patients with chronic heart failure (CHF) of ischemic origin of functional class II-III according to NYHA, aged 40-60 years with a history of myocardial infarction of 6 months, were examined up to 5 years. Depending on the presence of MS components, 3 groups of patients were identified: group I (n=80), patients without MS (CHF FC II—42, CHF FC III—38 patients); Group II (n=77) patients with various combinations of dyslipidemia (HDL-C <1.03 mmol/l; LDL-C >3.0 mmol/l) with abdominal obesity (AO), hypertension and hypertriglyceridemia (HTG) (CHF FC II—40, CHF FC III—37 patients); Group III (n=75) patients with various combinations of dyslipoproteinemia (DLP) and type 2 diabetes mellitus (DM2) with AO, hypertension and hypertriglyceridemia (CHF) (CHF FC II—36, CHF FC III—39 patients). When diagnosing MS, the International Diabetes Federation diagnostic criteria for MS were used (IDF, 2009). The study of the functional state of the kidneys included determination of the level of serum creatinine, urinary albumin excretion (determination of microalbuminuria (MAU ≥300 mg/l) in a single morning urine using indicator strips (Biosensor AN, Russia), glomerular filtration rate (GFR), calculated by the formula GFR EPI, which takes into account race, sex, age, serum creatinine. To calculate GFR using the CKD-EPI formula, you can use special applications for mobile devices (QxMDCalculator). Results When studying the parameters of the functional state of the kidneys in patients with group 1 CHF, 20 patients (25%) out of 80 were diagnosed with MAU. Serum creatinine clearance in this group was 89.0 ± 8.49 μmol/L, and the GFR level was 88.58 ± 8.36 ml/min. With the development of MS in group II patients, 41 out of 77 patients had MAU (53.2%). A decrease in GFR by 19.3% (P<0.01) was also found with an increase in serum creatinine levels by 22.7% (P<0.01), in contrast to the data from group I of the study. Further analysis of the parameters of renal function in CHF group III revealed a significant decrease in GFR (by 29.8%; P<0.001) with a significant increase in blood creatinine levels (by 31.8%; P<0.001) in relation to the data of group I. Also in group III of patients with CHF and MS (+DM2), microalbuminuria was detected in 47 patients (74.6%) out of 75. When comparing indicators of renal function between study groups II and III, there was a significant difference in the level of blood creatinine clearance and glomerular filtration rate by 21.3% and 20.1% (P<0.005), respectively. According to the classification of CKD, in group I of patients with CHF, stage I CKD was detected in 39.3%, in group II in 28.6% and in group III in 19.4%. CKD stage II was detected in group I in 46.4%, in group II in 50% of patients. 46.9% had CKD stage II of the disease in group III of the study. Also, in group II, 21.4% and group III, 43.7% were diagnosed with stage III CKD. V In group I, 35% had a high risk, 53.6% had a moderate and 14.3% had a low combined risk of developing cardiovascular complications in cardiorenal syndrome. Conclusion Thus, MS in patients with CHF aggravates renal dysfunction, which developed as one of the main pathogenetic links of CHF. It has been established that as MS progresses (addition of type 2 diabetes to other components of MS), the phenomena of functional renal failure increase. Violation of the functional state of the kidneys, the severity and nature of this dysfunction depends on the presence and nature of the representation of MS components.