Lipid peroxidation of liposome made of egg lecithin was induced by glucosone (D-arabino-hexos-2-ulose), a secondary product of Maillard reaction or glycation of protein. Lipid peroxidation was assessed with measurement of TBARS (thiobarbituric acid reacting substances), POV (peroxide value), and HPLC measurement of MDA (malondialde-hyde). EDTA and DTPA (diethylenetriamine-pentaacetic acid) in-hibited the lipid peroxidation assessed by each method described above, indicating involvement of metal ions. The observed reduction of Fe³⁺ to Fe²⁺ by glucosone might be a critical step of the lipid peroxidation. Our findings suggest a possible role of lipid peroxidation of low-density lipo-proteins (LDL) induced by glucosone in atherosis caused by diabetes mellitus.