Objective To investigate the relevant factors of coronary artery disease (CAD) in young people under 40 years of age. Methods The study population was 292 young patients accepting coronary angiography in Fuwai Hospital from July to December 2006, including 272 men and 20 women, with the mean age being 36.7±3.7 years. The diagnosis of CAD was made in the cases presenting ≥50%stenosis in coronary lumen in coronary angiography. Based on the diagnosis, 217 patients (204 men, 13 women) were assigned to CAD group, and 75 (68 men, 7 women) to non-CAD group. Clinical data and metabolic characteristics of the patients were collected and analyzed using t-test,χ2 test, and multinomial logistic regression with SPSS 8.0 software. Results Most study subjects were current smokers (209/292, 71.6%), and more than half had body mass index (BMI)>24 kg/m2 (230/292, 78.8%) and usually took high-fat diet (162/292, 55.5%). The proportion of heavy smokers (smoking history ≥10 years and ≥20 cigarettes per day) were significantly higher in the CAD group than in the non-CAD group [20.7%(45/217) vs. 9.3%(7/75), P=0.015)]. Heavy smoking [odds ratio (OR), 1.89;95%confidence interval (CI), 1.74-2.05], hypertension (OR, 1.56;95%CI, 1.48-1.65), alcohol (OR, 1.37;95%CI, 1.30-1.46), type 2 diabetes mellitus (OR, 1.37;95%CI, 1.25-1.50), high-fat diet (OR, 1.35;95% CI, 1.28-1.43), and BMI>24 kg/m2 (OR, 1.09;95% CI, 1.03-1.17) were factors related to CAD in the young patients (all P