Up to 30% of liver transplants will develop graft cirrhosis within 5 years after liver transplantation (LT) due to recurrent HCV-infection forwarding accelerated graft damage. Genetic variants of cytokines involved in the immune response may contribute to the degree of graft inflammation, fibrosis progression, and antiviral therapy outcome. The aim of our study was to analyze biochemical and histological inflammation extent based on protocol liver biopsies and to evaluate the role of genetic variants of IL-28b in HCV-related graft disease and antiviral treatment response. 183 patients, who underwent liver transplantation for HCV-induced liver disease, were genotyped for IL-28b (rs8099917, G ≥ T) by TaqMan Genotyping Assay. 56 of 159 patients have been successfully treated with interferon-based antiviral therapy. 605 protocol liver biopsies performed 0.5 to 10 and more than 10 years after transplantation were evaluated according to Desmet and Scheuer classification of inflammation and fibrosis. Prevalence of IL-28b-genotypes was correlated with histological severity of graft damage, levels of aminotransferases, occurrence of acute cellular rejection, pre-treatment viremia, and antiviral therapy outcome. Significant association of IL-28b-genotype distribution was observed to the median grade of inflammation (p < 0.001), mean levels of aminotransferases (ALT: p = 0.001, AST: p = 0.003), median pre-treatment viremia level within 1 year after LT (p = 0.046) and interferon-based antiviral therapy failure (p < 0.001). Among successfully treated patients, G-allele was significantly less frequent, and the genotype GG was not present at all. No differences were observed regarding acute cellular rejection (p = 0.798) and fibrosis stages (p = 0.586). IL-28b polymorphism seems to influence the degree of graft inflammation at biochemical and histological levels. G-allele might serve as a marker for graft inflammation and as a predictor for unfavorable antiviral therapy outcome in HCV-re-infected LT-population. Liver Transpl, 2011. © 2011 AASLD.