Evidence has accumulatd to support the hypothesis that atherosclerosis involves lipid imbalance as well as inflammatory responses mediated by macrophage and foam cells. These findings have been based on animal models. To rationalize animal use and to propose an alternative biological model, a technique was standardized for macrophage-foam cell isolation and culture. The cultures were characterized by non-denaturing polyacrylamide gel electrophoresis (PAGE) of nonspecific esterases and histochemical staining. This method has not been applied previously for the characterization of the non specific esterases from leucocytes. The biological model presented here can be used to study macrophage-foam cell responses related to atherosclerosis.