Aim: to analyze the histological kidney features in patients with chronic glomerulonephritis (CGN) and arterial hypertension (AH) and without it, to assess the relationship between serum interleukin-18 (IL-18) and histological signs of tubulo-interstitial kidney lesion in patients with CGN and saved renal function. Methods: eighty one patients with CGN. Blood samples for biomarkers were collected. The diagnosis of "chronic glomerulonephritis" was defined by the clinical, laboratory data and renal biopsies. Patients were divided into 2 clinical groups: patients with AH and without AH. We used data of renal biopsies to analyze the signs of kidney tubulo-interstitial tissue lesion in patients with CGN. Levels of serum IL-18 were measured by Bender Medsystems kits (Аustria). Results: according to the results of renal microscopy 88% patients had mesangial proliferative glomerulonephritis, 7%membranous nephropathy, 5%membranous proliferative glomerulonephritis. Patients with CGN and AH have more severe histological tubulo-interstitial lesion parametres than patients with CGN without AH. On the basis of rank correlation analysis we proved that serum IL-18 directly correlates with indicators of of tubulo-interstitial kidney tissue lesion 186 Oleg Kraydaschenko et al. in patients with CGN, strong direct relationship was found between the level of serum IL-18 and dystrophic changes in epithelial tubules (r = 0.81, p < 0.05). Diagnostics of dystrophic changes in epithelial tubules by determining of the serum IL-18 level is a highly sensitive and specific method, with the efficiency of 96.6%.