Sepsis was induced in rats by cecal ligation and perforation (CLP). Five and 15 hours post CLP, alveolar macrophage (AM), Kupffer cell (KC), and peritoneal macrophage (PM) were isolated and cultured for 18 hours. Culture supernatant was examined for bioactivity of tumor necrosis factor (TNF) and interleukin 6 (IL-6) and response to lipoplysaccharide (LPS) stimulation in vitro. Results showed that AM produced more TNF during sepsis as compared with KC and PM. Stimulation with LPS in vitro was responded only by AM at 15 hr after CLP. Pattern of IL-6 production was different from TNF while KC produced the highest level of IL-6 after induction of sepsis.