Highly hydrophobic surfaces, such as Teflon®AF, exhibit poor cell adhesion properties due to favored and selective adsorption of albumin. Serum albumin is the most abundant protein in blood plasma that can as act as a carrier for hydrophobic molecules such as free fatty acids, bilirubin, and lipid-based hormones. Due to its non-polar nature and overall abundance, albumin is preferentially adsorbed to hydrophobic surfaces, such as Teflon®AF, and is thought to reduce mammalian cell adhesion by masking or out-competing extracellular matrix proteins responsible for the initial cell adhesion. In contrast to these observations, our lab previously reported on the ability of primary bone marrow macrophages as well as secondary monocyte/macrophage cell lines IC-21, RAW 264.7, and J774A.1 to adhere to Teflon®AF coated surfaces. In this work, we further show that the observed adhesion was not an artifact of extracellular proteins present in the fetal bovine serum or adhesion proteins secreted by the cells themselves, but that the adhesion was significantly mediated only by the presence of albumin.