Background: The natural history of chronic hepatitis C (CHC) is characterized by gradual progression of hepatic fibrosis, which can lead to cirrhosis. The aim of our study is to examine the influence of ineffective antiviral therapy on progress of the liver disease in CHC patients. Material/Methods: Seventy-seven treated and non-treated CHC patients with two liver biopsies: baseline (BLB) and control (CLB) performed at least 12 months after treatment and at least 18 months from BLB in non-treated patients were studied. Twenty-eight CHC patients(age:40.3+/-9.2 yrs; 22M), non-responding to interferon therapy (all with pretreatment fibrosis), were compared with non-treated patients divided into subgroups NT1 (21 patients [age: 45.1+/-11.2 yrs; 10M] with fibrosis in BLB) and NT2 (28 patients [age: 34.7+/-12.6; 17M] without fibrosis in BLB).The baseline clinical data between study groups as well as activity grade and fibrosis staging scores of the paired biopsy samples were compared. Results: All three groups were comparable in terms of mean duration of the disease and interval between biopsies. There were no significant differences of clinical features in T and NT1 groups. In CLB, the patients from NT1 group presented non-significant worsening of staging and grading and in NT2 group a slight but statistically significant increase in grading was observed. In contrast, the treated patients had a slight, but significant improvement in liver histology. Conclusions: Antiviral treatment stopped the progression of liver disease in CHC despite the lack of biochemical and virological response. In non-treated patients a slight tendency to worsening of morphological parameters was observed

Keywords: chronic hepatitis C, progress of liver disease, treatment, nonresponders