Many lines of evidence suggest that LDL is oxidized in vivo and that ox-LDL is present in the artery wall. But the oxidation of VLDL and HDL in vivo has not been reported yet. A study on effects of high cholesterol diet on oxidative modification of LDL, VLDL and HDL in rabbits was made. The control group (n = 8) was fed on routine diet, and the experimental group (n = 8) on high cholesterol diet (routine diet supplemented with 5% lard, and 0.5 g cholesterol a day for each rabbit) for 12 weeks. The serum LDL, VLDL and HDL were isolated by the density gradient ultra centrifugation. The oxidative modification of LDL, VLDL and HDL was identified by agarose gel electrophoresis, absorbance at 234 nm and fluorescence of TBARS. The results showed that serum TC, TG and TBARS in the experimental group were significantly higher than these of the control group (P < 0.01). The electrophoretic mobility of LDL, VLDL and HDL was increased, and absorbance at 234 nm and TBARS of LDL, VLDL and HDL in the experimental group were significantly higher than these of the control group (P < 0.01). These results suggest that not only LDL but also VLDL and HDL were oxidatively modified in vivo in rabbits after fed on high cholesterol diet.