['We investigated lipid metabolism in patients with chronic hepatitis C virus (HCV), serotype 1, undergoing combination therapy with PEG-IFN alpha-2b (PEG-IFN) and ribavirin (RBV).', 'A total of 185 patients with chronic HCV (HCV serotype 1; HCV RNA levels >/= 100 KIU/mL) who received a combination of PEG-IFN and RBV were enrolled.', 'Sustained virological response (SVR) was obtained in 82 cases (44.3%). The median age, red blood cell and platelet counts differed significantly between the SVR and non-SVR groups before treatment. However there was no significant difference between total cholesterol (TC), LDL-cholesterol (LDL-C) and triglyceride (TG) levels before treatment. TC and LDL-C levels decreased during the treatment in both groups. In the SVR group, TC and LDL-C levels increased quickly after the end of the treatment and were higher than those before treatment. On the other hand, TC and LDL-C levels returned to pretreatment levels in the non-SVR group and were significantly lower than in the SVR group. TG levels were elevated in both groups after the beginning of treatment. After the end of treatment, this elevation persisted in the SVR group, while TG levels returned to pre-treatment levels in the non-SVR group. There was a significant difference in TG levels at 24 weeks after the end of the treatment between the 2 groups. In the non-SVR group some patients achieved normalization of ALT (alanine aminotransferase) but persistence of normal ALT levels did not contribute to the increase of TC and TG.'] Does treatment of hepatitis C virus with peg-interferon and ribavirin combination therapy significantly affect lipid metabolism?