In previous papers we reported that endocrine disrupters (EDs) such as diethyl stilbesterol (DES), 4,4'-isopropylidene diphenol (Bisphenol A: BPA), bis (2-ethylhexyl) phthalate (EHP) and p-nonylphenol (NP) stimulated proliferative responses and cytokine productions of murine spleen cells and thymus cells in vitro. In this paper we report the effect of EDs on murine macrophage functions in vitro. DES, BPA, EHP and NP stimulated thioglycolate-induced peritoneal exudate cells (macrophages) to produce cytokines such as interleukin (IL)-1, IL-6, IL-12, tumor necrosis factor and macrophage chemotactic protein- 1. The effect of these EDs was observed at the concentrations of 10(-6)-10(-8) M, and the maximum response was obtained at 10(-7 M.) The accessory function for T cell activation and CD86 expression, an important molecule for accessory function, was enhanced in EDs-treated macrophages. These results suggest that EDs have modulating activities of macrophage functions.