['Low gamma-glutamyltransferase (GGT) level was shown to be an independent predictor of a sustained virological response (SVR) in chronic hepatitis C. We aimed to determine factors associated with high GGT level, and to evaluate whether low GGT level is an independent predictor of a SVR in chronic hepatitis C genotype 1.', 'We retrospectively reviewed our data of patients with chronic hepatitis C genotype 1 treated with pegylated interferon-α and ribavirin. Baseline features were compared between patients with normal and high GGT levels. Factors associated with high GGT level and those associated with a SVR were determined by univariate and multivariate analysis.', 'This study included 57 patients. Mean age was 52.28±9.35 years. GGT levels was elevated in 27 patients (47.4%). GGT levels were normal in 63.3% of the patients who achieved a SVR and in 40.7% of those who did not achieve a SVR (p>0.05). By multivariate logistic regression analysis, the presence of cirrhosis (odds ratio [OR], 9.41; 95% confidence interval [CI], 1.08 to 102.61) and female gender (OR, 6.77; 95% CI, 1.23 to 37.20) were significantly associated with high GGT level, and only rapid virological response was associated with a SVR (OR, 8.369; 95% CI, 1.82 to 38.48).'] Does a lower serum gamma-glutamyltransferase level predict a sustained virological response in patients with chronic hepatitis C genotype 1?