BACKGROUND. To date, the study of the factors involved in the glomerular-tubular pathological connections leading to damage to the tubulointerstitial tissue is one of the topical areas of nephrology. THE AIM: to study the effect of MCP-1 in the development of tubulointerstitial fibrosis as a factor in the irreversible progression of chronic renal failure. PATIENTS ANDMETHODS. Prospective observation and retrospective analysis of case histories were carried out, which included a total of 75 patients with primary chronic glomerulonephritis. RESULTS. The average age of the patients was 36.7 ± 12.3 years, of which 52 were males, 23 were women. The average length of service in a nephrological disease was 3.0 [1.0; 5.0] years. The calculated GFR values are 87.3 ± 31.2 ml / min / 1.73 m2. In the general population, the moderate degree of MCP-1 expression, estimated at 2 points, was 35 %, pronounced expression was found in 25 % of the respondents. In the mesangium of the glomeruli and in macrophages, the expressed degree of MCP-1 expression was 20 % and 16 %, respectively, which characterizes MCP-1 as a marker produced by resident cells. When studying the relationship of MCP-1 in blood with clinical parameters, a correlation was found with the values of total protein (Rs= –0.43; p <0.05), with erythrocyturia (Rs= –0.28; p <0.05), as well as with an albumin level (Rs= –0.5; p <0.05), which indicates the role of MCP-1 in the development of nephritic forms of glomerulonephritis. Depending on the severity of MCP-1 expression in biopsy specimens, the incidence of focal tubulointerstitial fibrosis with MCP-1 expression estimated at 1 point was 13.3 %, 2 points – 14.3 %, 3 points – 44.0 %. The revealed significant correlation between the serum level of MCP-1 and the severity of tubulointerstitial fibrosis confirms the MCP-1-mediated mechanism of progression of CKD. CONCLUSION. The relationship of serum and tissue forms of MCP-1 with the progression of tubulointerstitial fibrosis in chronic glomerulonephritis has been demonstrated. MCP-1-induced mesangial cell plays a critical role in the development of renal tubular damage, and its increased expression is associated with progressive tubulointerstitial fibrosis and decreased renal function.