Background:Liver steatosis is commonly associated with CHC.The aim of our study was to assess the changes in liver steatosis (LS)after antiviral treatment in relation to type of response. Material/Methods: Results of paired liver biopsy (before and at least 12 months after the end of interferon alone or with ribavirin treatment)of 91 CHC patients were compared.Liver specimens were assessed according to Ishak`s criteria;median interval between baseline and 2 nd biopsies was 32 months.69 of them patients (F19/M50;age:43 ±10yrs)were no sustained responders (NSR)and 22 (F12/M10;age:38 ±10yrs)were sustained responders (SR).The control group (CG)was 50 (F25/M25; age:39(13yrs) non-treated CHC patients (interval between 1 st and 2 nd biopsy at least 18 months;median 24 months).The total number of patients with LS (>1%involved hepatocytes)in both biopsies and changes in fibrosis stage were evaluated. Results:Between 1 st and 2 nd biopsy there were no significant changes in mean stage (2.4 ±1.8 vs.2.4 ±1.7 and 0.6 ±0.9 vs. 0.7 ±1.1)as well as in frequency of LS (65%vs.68%and 44% vs.44%)in NSR and CG groups,respectively.In 2 nd biopsy, among SR patients a significant decrease in fibrosis stage was noted (1.7 ±1.4 vs.0.6 ±1.4 in 1 st and 2 nd biopsy respectively; p=0.015)as well as disappearance of LS (in all but one patient).The maximum loss of LS was observed in non-diabetic normolipaemic 44-old women:more than 40%at 1 st and 0%in 2{ig nd}biopsies in the presence of no significant changes in the levels of cholesterol,triglycerides and BMI value. Conclusions: Too small number of patients have made impossible to analyse LS in relation to HCV genotypes but our observations suggest that the loss of steatosis appears before the regression of fibrosis in almost all sustained responders patients.Moreover,our study seems to confirm the reports of the viral nature of liver steatosis in chronic hepatitis C.