The aim of the study is to reveal and treat the side effects of the combined antiviral therapy - Peginterferon and Ribavirin in patients with chronic Hepatitis C. During 2004-2006 years, 40 patients in the ambulatory department of the Infectious Diseases Clinic of the State Medical University were investigated. All the patients were administered pegilated interferon and ribavirin after special procedures. The following side effects on the antiviral treatment were grouped: flu-like, cardiovascular, gastrointestinal, neuro-psychiatric, dermatological and hematological. Frequency, severity and duration of all unfavorable symptoms were independent of Hepatitis C genotype, though the adherence to the medications was better in younger age groups and the dose correction where required after the age 45.