NAD(P)H:quinone oxidoreductase 1 (NQO1) is a cytosolic enzyme that catalyzes the two-electron reduction of numerous quinoid compounds into their less toxic form, thus NQO1 protecting cells against oxidative stress. The gene coding for NQO1 has a single nucleotide polymorphism (C -> T) at nucleotide position 609 (proline to serine substitution at position 187 in amino acid sequence (P187S)) (rs1800566) of the NQO1 cDNA which results in very low enzimatic activity, so it would be expected that individuals with the homologous NQO1 C609T polymorphism would have a susceptibility developing cancer. Previous studies of the association between functional NQO1 C609T polymorphism and several human cancers have had mixed findings but association of NQO1 C609T polymorphism with hepatocellular carcinoma (HCC) development has yet to be investigated. In this study, we aim to evaluate the the association of NQO1 C609T with the risk of hepatocellular carcinoma (HCC) development among Turkish population. NQO1 C609T polymorphism was investigated in 167 confirmed subjects with HCC and 167 cancer-free control subjects matched on age, gender, smoking and alcohol consumption by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. There is no association between the allel or genotype of NQO1 C609T polymorphism and HCC development risk in the Turkish subjects examined (p>0.05). Our result demonstrate for the first time that the NQO1 C609T polymorphism is not a genetic susceptibility factor for HCC in the Turkish population. Independent studies are need to validate our findings in a larger series, as well as in patients of different ethnic origins.