To investigate apolipoprotein(apo) E polymorphism and its relationship with serum lipids and apolipoproteins in Chinese patients with endogenous hypertriglyceridemia(HTG).apoE genotype was assayed by polymerase chain reaction- restriction fragment length polymorphism(PCR-RFLP), serum lipids were determined by enzyme method, and apolipoproteins were measured by radial immunodiffusion assay in 225 endogenous HTG patients whose fasting serum TG levels were > or = 2.26 mmol/L and in 230 healthy subjects whose fasting serum lipids levels were TG0.05). Both in HTG group and control group, the genotype of apoE2 had higher serum TG and apoE levels, lower LDLC level and decreased apoE/apoCIII ratio as compared with the genotype of apoE3 or apoE4(P<0.001).Allele epsilon(2) of apoE gene was associated with higher serum TG and apoE levels and lower serum LDLC level, and the lower ratio of apoE/apoCIII was associated with the higher serum level of TG in endogenous HTG.