Aim To study the relationship between apolipoprotein E (apo E) genotic polymorphisms,serum lipid and the incidence of myocardial infarction in the old people. Methods Apo E genotypes of 97 controllers and 47 myocardial infarction patients were genotyped by polymerase chain reaction restriction fragment length polymorphism and their serum lipid were measured at the same time. Results The most frequency genotype was E3/3 and the next was E3/4 in the two groups. The estimated apo E allele frequencies in the sample of control group were 0.0309, 0.8918 and 0.0773 for the ε2, ε3 and ε4 alleles, respectively. The estimated frequencies of the ε2, ε3 and ε4 alleles in the sample of myocardial infarction group were 0.0306, 0.8163 and 0.1531, respectively. The frequency of ε4 allele carriers in the myocardial infarction group was bigger than in the control group. The frequency of E3/4 genotype of myocardial infarction group was also higher than the control group (P<0.05). Compared to apo E genotype E3/3, a risk associated with genotype E3/4 increased in the myocardial infarction group. The OR of genotype was 5.52 with 95% CI 1.02～29.80(P<0.05) after adjusted by sex, age, and lipid pool. Conclusion Apo E genotype E3/4 was the independent risk factor for myocardial infarction in Shanghai. The genetic effect on the occurrence of myocardial infarction was more directly in women than in men. 还原