Apolipoprotein E (apoE, protein; APOE, gene) plays a major role in lipoprotein metabolism and lipid transport. Many investigators have described associations between apoE genotypes, coronary artery disease (CAD), and other risk factors. The aim of this study was to investigate the association between apoE genotypes and serum lipid profiles in a healthy population of 220 volunteers at Kaohsiung in Taiwan. Other CAD risk factors such as serum levels of apolipoprotein A-I (apoA-I), apolipoprotein B, (apoB), homocysteine (Hcy), folate, and vitamin B12 were also measured. ApoE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In the study population, the frequency of apoE allele epsilon3 was greatest (85.2%); the frequency of epsilon2 was 8.4%; and that of epsilon4 was 6.4%. The serum apoA-1/apoB ratio showed significant difference among the 3 apoE genotype groups (p 0.0001); the apoA-1/apoB ratio was 1.9 +/- 0.1 (mean +/- SD) in the epsilon2 group, vs 1.4 +/- 0.04 and 1.5 +/- 0.12 in the epsilon3 and epsilon4 groups, respectively. No significant associations were found between APOE alleles and the serum levels of the various lipids or other CHD risk factors.