CETP activity reduces plasma HDL-cholesterol concentrations, a correlate of increased risk of atherosclerotic events. However, our recent findings suggest that CETP expression in macrophages promotes an intracellular antioxidant state, reduces free cholesterol accumulation and phagocytosis, and attenuates pro-inflammatory gene expression. To determine whether CETP expression in macrophages affects atherosclerosis development, we transplanted bone marrow from transgenic mice expressing simian CETP or non-expressing littermates into hypercholesterolemic LDL receptor deficient mice. CETP expression did not change lipid-stained lesion areas but decreased macrophage content (CD68), neutrophil accumulation (LY6G) and aorta content of young male transplanted mice and decreased LY6G, TNF-α, iNOS and nitrotyrosine (3-NT) in aged female transplanted mice. These findings suggest that CETP expression in bone marrow-derived cells reduces inflammatory features of atherosclerosis. These novel mechanistic observations may help explain the failure of CETP inhibitors to reduce atherosclerotic events in humans.