Background and objective Apolipoprotein E is a constituent of lipoproteins with considerable variation due to cysteine-argin-ine exchanges. We investigated the relationship between apo E gene polymorphism and the occurrence of coronary artery disease (CAD) in the older population of northern China. Methods The distribution of the HhaI polymorphisms of the apolipoprotein E gene was determined among 55 patients with CAD (CAD group), which was compared with that of 36 elderly subjects without CAD (control group). Results Genotype distributions at both sites (apo E gene 112-bp and 158-bp sites ) were different between the CAD and control groups. The CAD group had lower apolipoprotein E“ε2”frequencies than the control group (P<0.05). Conclusion Individuals with apolipoprotein E“ε2”are likely to have a reduced risk of developing coronary artery disease as demonstrated by elderly subjects in Northern China. Background and objective Apolipoprotein E is a constituent of lipoproteins with similar variation due to cysteine-argin-ine exchanges. We investigated the relationship between apo E gene polymorphism and the occurrence of coronary artery disease (CAD) in the older population of northern China. Methods The distribution of the HhaI polymorphisms of the apolipoprotein E gene was determined among 55 patients with CAD (CAD group), which was compared with that of 36 elderly subjects without CAD (control group). Results Genotype distributions at both sites -bp and 158-bp sites were different between the CAD and control groups. The CAD group had lower apolipoprotein E “ε2 ” frequencies than the control group (P <0.05). Conclusion Individuals with apolipoprotein E “ε2” are likely to have a reduced risk of developing coronary artery disease as demonstrated by elderly subjects in Northern China.