Aim Oxidized low density lipoprotein (LDL), verylow density lipoprotein (VLDL ) and high densitylipoprotein(HDL) were occured in vivo in endogenoushypertriglyceridemia (HTG ) human.Methods Human plasma triglycerides (TG), totalcholesterol (TC), high density lipoprotein cholesterol(HDLC), apolipoproteins A l, AⅡ, B₁₀₀, CⅢ, Eand lipoperoxide (LPO) levels in 25 endogenous HTGpatients whose plasma TG levels were>2. 26 mmol/Land TC<6. 21 mmol/L, and in 25 normal age-matchedpersons (TG < 2. 26 mmol/L, TC < 6. 21 mmol/L )were measwred. Blood glucose, TC, TG and HDLCwere performed by enzyme method. Plasmaapolipoprotein were determined by radial immunuodiffusion (RID) assay. The human plasma LDL, VLDLand HDL were isolated by the one step density gradientultra-centrification method. The oxidative modificationof LDL, VLDL and HDL was identified by agarose gelelectrophoresis, absorbance at 234 nm and fluorescenceof thiobarbituric acid reaction substance(TBARS).Results The results showed that plasma TG, LPOand apolipoprotein B₁₀₀ levels in endogenous HTGgroup were significantly higher than that of the controlgroup (p<0. 01). Plasma HDLC and apolipoprotein AⅠ contents in endogenous HTG group were significantly lower than that of the control group (p< 0.01). The electrophoretic mobility of LDL,VLDL andHDL was increased and absorbance at 234 nm andTBARS of LDL, VLDL and HDL in endogenous HTGgroup were significantly higher than that of the controlgroup (p<0. 01).Couclusion The results suggest that not only LDLbut also VLDL and HDL were oxidatively modified invivo of endogenous HTG patients-