Aim To study apolipoprotein (apo) E polymorphism and its relationship with plasma lipids and apolipoproteins in Chinese patients with endogenous hypertriglyceridemia(HTG). Methods ApoE phenotype was assayed by isoelectric focusing (IEF) and immunoblotting, serum lipids were determined by enzyme method and apolipoproteins were measured by radial immunodiffusion assay in 93 endogenous HTG patients whose fasting serum TG levels were ≥2.26 mmol/L, TC<6.21 mmol/L and 288 healthy subjects whose fasting serum TG levels were<1.82mmol/L, TC<6.21 mmol/L. Results The fasting serum TG, TC, apoB100, CⅡ, CⅢ and E levels were significantly higher and apoAI level was lower in the endogenous HTG group than those in the control group (P<0.001). ApoE phenotype and allele frequency distribution of the endogenous HTG group (E3/3 68.82%, E2/3 17.20%, E3/4 9.68%, E2/4 4.30%, E4/4 0.00%, E2/2 0.00%, ε3 0.8226, ε2 0.1075, ε4 0.0699)was similar to that of the control group( E3/3 72.92%, E2/3 13.54%, E3/4 10.76%, E2/4 1.04%, E4/4 1.74%, E2/2 0.00%, ε3 0.8507, ε2 0.0729, ε4 0.0764). Compared with apoE3(E3/3) or apoE4(E3/4+E4/4) subgroup, apoE2(E2/3+E2/2) was associated with lower serum TC and apoB100 levels (P<0.05) and higher apoE level (P<0.05) in the control group, but no significant difference was observed in endogenous HTG group. Conclusion The apoE phenotype and allele frequency distribution of the endogenous HTG group was similar to that of the control group. ApoE2 was associated with lower serum TC and apoB100 levels and higher apoE level in the control group. 还原