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 Hhal 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"el"frequencies than the control group (/><0.05). Conclusion Individu-als with apolipoprotein E"e2"are likely to have a reduced risk of developing coronary artery disease as demonstrated by elderly subjects in Northern China.