Background:To compare the efficacy of IFT in patients depending on the histological activity degree and disease stage.Material/Methods: The results of IFT have been analysed in 50 patients with CHC.There are 40 males and 10 females in the studied group.Mean age of patients was 36.6 ±16.6.All the patients underwent liver biopsy before IFT and in 6 months after its accomplishment.The histological examination has been made according to Knodell scoring system.31 patients had CHC of mild activity (a necroinflammatory score was in range 1 –8),19 patients –of moderate activity (a necroinflammatory score was in range 9 –12).Fibrosis score of 0 was in 10 patients, fibrosis score of 1 –in 24 patients,fibrosis score of 3 –in 15 patients.All the patients were receiving monotherapy with a -2 b Interferon preparations within 6 months.The groups were compared according to biochemical response rate (BR),namely,reduction of ALT activity on the background of IFT,virological response (VR)–disappearance of RNA HCV after IFT course,morphological response (MR)–reduction of inflammation and fibrosis degree in the control biopsy.Results:The rate of BR did not differ significantly in patients with hepatitis of mild activity in comparison with ones who had hepatitis of moderate activity (25/31 v.6/19,respectively, p>0.05).VR was in 10/31 patients with hepatitis of mild activity v.4/19 patients with hepatitis of moderate activity (p>0.05),MR was in 30/31 patients with hepatitis of mild activity and in 6/19 patients with hepatitis of moderate activity (p>0.05).BR was found out evidently more frequently in patients with fibrosis 0 in comparison with the patients who had fibrosis 3 (9/10 patients v.6/15,respectively p0.3).VR was significantly more frequent in patients with fibrosis 0 as compared with the patients having fibrosis 1 and fibrosis 3(7/10 v.4/24,p0.05).Conclusions:1.Patients with chronic hepatitis C and progressive fibrosis stage had significantly low rate of BR and VR on IFT in comparison with ones who did not have fibrosis in liver biopsy,it should be taken into consideration while admi- nistering IFT.2.Histological activity degree did not influence on the efficacy of IFT in the studied group.