Abstract: Objective To investigate the relationship between nicotinamide adenine dinucleotide hydrate/nicotinamide adenice dinucleotide phosphate hydrate(NADH/NADPH) oxidase p22phox gene C242T polymorphism and coronary heart disease(CHD).Methods A hospital-based case-control study was conducted among 309 premature CHD,437 late-onset CHD patients and 470 controls.Polymerase chain reaction restriction fragment length polymorphism(PCR-RFLP) was used to detect the polymorphism.Univariate and multivariate logistic regression models were performed to estimate odds ratios (ORs) and 95% confidence interval(CI) of CHD.Results The odds ratios of CT + TT versus CC genotype of C242T polymorphisms for CHD between early-onset CHD group and controls were statistically significant in both univariate logistic model(OR=1.58,95% CI:1.07-2.34) and multivariate logistic model(OR=1.74,95% CI:1.16-2.62).For the comparison between late-onset CHD group and controls,the odds ratio was statistically significant(OR=1.48,95% CI:1.03-2.13) in univariate logistic model.How ever,when comparing early-onset CHD group with late-onset CHD group,the odds ratios in neither univariate analysis nor multivariate logistic regression were statistically significant.Conclusion T allele of p22phox gene C242T polymorphism may be a risk factor for CHD.