Abstract Circulating monocytes differentiate into macrophage (MΦ) subpopulations in response to environmental signals. Carotenoids may reduce MΦ oxidant stress, alter the inflammatory response, and lower risk of atherosclerosis. These observations prompted us to determine the effects of β-carotene, lycopene, astaxanthin and lutein on differentiation of human monocytes into MΦs (M1 and M2) phenotypes. Monocyte-to-MΦ differentiation was driven by treatment for 6 days with GMCSF or MCSF ± individual carotenoids. M1 MΦs (+GMCSF) were activated with LPS+IFNγ; M2 MΦs (+MCSF) were activated with IL-4. We validated that M1 and M2 cells showed distinct morphologies and expression patterns (qRT-PCR) of scavenger receptors (SR-A, LDLR, CD36, SR-B1) and cytokines (IL-10, IL-12). M1 and M2 markers (CD14, CD16, CD36, CD80, CD163) and cytokines (PGE2, IL-6, IL-8, IL-10, IL-12, TNFα, IFNγ) were confirmed by flow cytometry. Expression of CD14, CD16, CD36, CD163, and IL-10 was higher in M2 than M1 MΦs. Lycopene and astaxanthin decreased SRA, CD36 and LDLR mRNA levels in M1 cells but had no significant effect on M2 cells. Lutein also reduced SRA, CD36 and IL-10 expression in M2. Conversely, β-carotene increased M1 and decreased M2 expression of SRA, CD36, IL-10 and IL-12. Results show individual carotenoids can regulate MΦ scavenger receptor and cytokine expression. We speculate that carotenoids influence MΦ polarization, thereby inhibiting cholesterol accumulation in MΦ-derived atherogenic foam cells.