Earlier we have discovered serum factor responsible for atherogenicity. This is multiple modified low density lipoprotein circulating in the blood of patients. I would like to specially emphasize that this modification is not only oxidative modification. I have no time to list all changes of lipoprotein particle in details. There are numerous physico-chemical characteristics which are altered in lipid, protein, and glycoconjugatemoiety of lipoprotein particle. The most important property of multiple modified LDL is the ability to accumulate lipids in arterial cells.