Aim To study the distribution of low density lipoprotein (LDL) subfractions and its susceptibility to in vitro oxidation in patients with chronic kidney failure (CKF). Methods LDL subfractions were isolated from plasma by non equilibrium density gradient centrifugation directly, and distribution of LDL subfractions in CKF patients were analyzed. The continuous monitoring of LDL oxidation by absorbance measurements at 234 nm was used to analyze the susceptibility of LDL and its subfractions to Cu 2+ mediated oxidation in patients with CKF. Results The frequency distributions of LDL subfractions in CKF patients had no different from that of control. The lag time in the test for LDL oxidizability in CKF patients was shorter than that in control (48.2±24.7 vs 93.3±37.2 min, P<0.05). The degree of oxidized LDL was correlated with the lag time of LDL oxidizability. The total amount of conjugated dienes and the maximal rate of oxidation had no difference. Conclusions Circulating LDL isolated from CKF patients is more susceptible to oxidation in vitro than that of controls, this may be associated with the level of oxidative modification LDL.