Aim To study the effects of low density lipoprotein -immune complexes (LDL-IC) on the cholesterol metabolism and on the expression of low density lipoprotein receptor (LDLR) in monocyte- derived macrophages. Methods PMA-treated THP-1 cell were used as a model of monocyte-derived macrophages. Quantitative analysis of intracellular cholesterol content was performed by cholesterol enzyme link assays. The expression of LDLR mRNA was detected by reverse transcription polymerase chain reaction(RT-PCR)and LDLR protein was detected by Western blot. Results The intracellular cholesterol level treated with LDL-IC was higher than other groups treated with LDL, IgG-IC and negative control. Both LDLR mRNA and LDLR protein values of macrophages stimulated by LDL-IC were significantly enhanced. Conclusions Incubating with LDL-IC can not only markedly elevate the intracellular cholesterol content but also promote the expression of LDLR mRNA and protein which suggest LDL-IC may be an important factor during the development of atherosclerosis.