AIM: To assess the role of transforming growth factor-β1(TGF-β1), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (Bfgf) in the pathogenesis of fibrosis associated with chronic hepatitis C (CHC)and to evaluate the influence of the antiviral therapy on above parameter levels depending on the treatment results (complete response or no response).METHODS: Study group included 100 patients with CHC, in whom fibrosis in liver specimens was assessed (Scheuer fibrosis score: 1-4 points). Control group included 30 subjects with antibodies anti-HCV present and persistently normal ALT level, without fibrosis (Scheuer fibrosis score: 0 points). Concentration of studied parameters was assayed in the serum by immunoenzymatic method before and after the therapy with interferon alpha-2b and ribavirin.RESULTS: TGF-β1 levels were significantly higher in the study group compared to the control group (35.89 vs 32.37ng/Ml; P=0.023). Such differences were not found in VEGF and Bfgf levels. In patients showing complete response (negative HCV RNA and normal ALT level), significant increase in VEGF (112.8 vs 315.03 pg/Ml; P＜ 0.05) and Bfgf (2.51 vs 15.79 pg/Ml; P=0.04) levels were found. Significant decrease in TGF-β1 level was observed both in responders (37.44 vs 30.02 ng/Ml; P=0.05), and in non-responders (38.22 vs 30.43 ng/Ml; P= 0.043).Bfgf levels before the treatment were significantly lower (2.51 vs 5.94 pg/Ml; P=0.04), and after the treatment significantly higher (15.79 vs 4.35 pg/Ml; P=0.01) in patients with complete response than in those with no response.CONCLUSION: Among the analyzed parameters TGF-β1 seems to play the most important role in the pathogenesis of fibrosis in CHC. Levels of this factor are significantly lower in subjects who do not have fibrosis developed in them. Good therapeutic effect in CHC patients is associated with significant changes in TGF-β1,VEGF, and Bfgf levels. Bfgf seems to have the highest usefulness in the prognosis of treatment efficacy.