The critical analysis of baseline factors has been found to be useful to predict virologic nonresponse (NR), relapse, or sustained virologic response (SVR) in patients infected with hepatitis C virus (HCV) who receive antiviral therapy. In the present retrospective study we tried to find out whether gamma-glutamyltranspeptidase (GGT) may be one of the baseline factors which are of special predictive power. We analyzed, in patients with different treatment outcomes, the predictive power of established baseline factors either in combination with GGT or by evaluating the predictive value of GGT independently.