A large number of growth factors and cytokines involved in the processes of atherogenesis.A variety of in vitro and in vivo studies gave indicated that tumor necrosis factor (TNF)and nitric oxide (NO)have close relation to atherogenesis. In order to find out the secretion of TNF and NO production by lipopolysaccharide-stimulated macrophages preincubated with minimally modified low density lipoprotein(MM LDL)and oxidized low density lipoprotein(OLDL). The results were that after 48 hours treated, the secretion of TNF induced by MM LDL increased up to 2-fold, and the increase of NO production could be up to 5-fold. However, OLDL sharply inhibited the production of TNF in a concentration-and time-dependant with maximum inhibition(>90%)after 48 h preincubation with OLDL,and NO production did not increase(p>0.05). Concerning with other studies, we suggested that in the different stages of atherogenesis, tbe amount of production of TNF and NO by vessal cells might be different, but more evidents in vivo are needed to find out this mechanism.