Aim The search for the relation between macrphage colony-stimulating factor (MCSF), scav- enger receptor (SR), oxidative modified low density lipoprotein (OLDL) and atherosclerosis (As). We studied the effect of recombinant human MCSF (rhM- CSF) on the SR passway of mouse peritoneal macrophage (MPM) and the effect of rhMCSF on cel-lular cholesteryl ester (CE) accumulation caused by OLDL.Methods Mouse peritoneal macrophages (MPM) were collected by routine method. LDL was isolated by density gradient ultracentrifugation, oxidized by CuCl2 and labeled either with 3, 3-dioctadecyl indocar- bocyamine (Dil) or with 125 I. The binding of DiI- OLDL and degradation of 125 I-OLDL by MPM and the intracellular content of CE were measured according to the methods of Stephen, Gold stein and Heider respec- tively.Results Recombinant human MSCF could increase the number of SR on cultured MPMs and enhance the binding and degradation of OLDL with a dose-and time-dependent mode. The cellular CE accumulation caused by OLDL was also enhanced by addition of rhMCSF.Conclusions MCSF may enhance the cellular binding and degradation of OLDL by increasing the number of SR on MPMs, hence increase the cellular CE content and promote the formation of foam cells in the vascular wall.