Aim: To study the abnormal composition of serum low density lipoprotein (LDL) and its level of oxidative modification in patients with diabetes mellitus.Methods: The serum lipids, apoIipoprotein concentritions, triglyceride (TG) and total cholesterol (TC) level of LDL, oxidative LDL in patients with diabetes mellitus (DM) and control group wete analyzed.Results: The DM patients had abnormal lipid metablism, significantly higher level of total TG, TG in LDL, and TG/TC. The level of oxidatively modifid LDL was significantly higher and the oxidatively modified LDL to total LDL ratio was positivily correlated with TG/TC ratio in patients (r = 0. 36, P< 0.01 ) and control (r= 0. 29, P<0. 05 ). Conclusion: The compositional abnormalities of LDL are related to its oxidative modification in DM patients, and may be associated with increased risk for coronary artery disease.