The current study was performed to assess any association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and risk of lung cancer in Henan province. This case-control study involved94 patients with newly histological confirmed lung cancer and 78 healthy controls. Genotyping was achieved with peripheral blood lymphocytes DNA and association of the polymorphism with risk of lung cancer was estimated by unconditional logistic regression analysis. The frequencies of the MTHFR 667TT genotype were 37.2% in cases compared with 23.1% in controls (χ2 = 4.008, P = 0.045). Individuals with the 667CC/CT genotype displayed a significantly reduced risk of lung cancer compared with those with the TT genotypes [adjusted odds ratio (OR), 0.506; 95% confidence interval (95% CI), 0.258 - 0.991]. The C667T polymorphism might have a significant effect on the occurrence of lung cancer in Henan province.