The role of alcohol consumption and aldehyde dehydrogenase 2 (ALDH2) genotype in hepatocellular carcinoma (HCC) development remains uncertain. We conducted genotyping of the ALDH2 rs671 single nucleotide polymorphism in 298 patients with HCC and 889 non-cancerous healthy controls. We assessed associations stratified by sex and alcohol consumption status. Distribution of ALDH2 rs671 variant genotypes differed significantly between HCC patients and controls (ptrend=0.0311). Logistic regression analyses indicated that compared to the wild-type GG genotype, the heterozygous variant AG genotype and homozygous variant AA genotype conferred 1.22- and 1.77-fold increases in HCC risk (p=0.1794 and 0.0150, respectively). Allelic frequency analysis showed that the A allele was associated with a 1.29-fold increased HCC risk (p=0.0123). Additionally, AA genotype carriers had significantly higher HCC risk than GG genotype carriers among males (p=0.0145) and non-alcohol drinkers (p<0.001). HCC risk is influenced by ALDH2 genotype, with effects modified by sex and alcohol consumption. Particularly, individuals with the ALDH2 rs671 AA genotype should avoid alcohol consumption, especially males.