Because hepatitis C virus (HCV) genotypes have raised considerable interest as variables that influence chronic hepatitis C progression, a case-control study was conducted to estimate their effects on patients with cirrhosis. Case patients (n = 46) had tested positive for anti-HCV antibody and HCV RNA and were residents of the study area who had cirrhosis recently diagnosed. Controls (n = 138) were drawn randomly from a residents' cohort from the same area. Demographic and other inferomation were recorded. Presence of HCV infection, presence of HCV RNA, and HCV genotypes were assessed. Crude, stratified, and logistic regression analysed were performed. HCV genotype 2a/c occurred in 84 controls (60.9%) and 9 case patients (19.6%); HCV genotype 1b was found in 45 controls (32.6%) and 34 case patients (73.9%). HCV 1b genotype showed an independent effect on the risk of cirrhosis (odds ratio, 7.49; 95% confidence interval, 3.15-17.81). No significant effects related to other variable were observed. These results indicate that the genetic diversity of HCV phylogenetic variants may explain differences in biological behaviors