Mycoplasma pneumoniae is a common respiratory pathogen, that is responsible for mild acute respiratory infections and severe central nervous system infections such as meningitis and encephalitis. However, the mechanisms of theses diseases are poorly understood. The oncogenic potential of mycoplasmas was recently carefully realized that they were shown to cause chromosomal changes and in vitro cell transformations. However, few studies have been reported the prevalence of mycoplasmas infection in human cancers. This study was carried out to determine the level of inflammatory cytokines in the culture supernatants of mouse astrocytes stimulated with LPS, IFN-${gamma}$, M. pneumoniae antigen and B-16 melanoma cells. Astrocytes ($1{ imes}10^6;cell/ml$) were cultured in the 24 well plate, and was added 10 ng/ml of LPS, $10;{mu};g/ml$ of IFN-${gamma}$, 10 mg/ml of M. pneumoniae antigen, and B-16 melanoma cells in each well, and was incubated at $37^{circ}C$ 5% $CO_2$ incubator. The $100;{mu}l$ of culture supernatant of each well was harvested on 24, 48, 72 hours after incubation, for the quantitative assay of each cytokines by the ELISA kits (Genzyme, USA). The concentration of IL-$1{eta}$, IL-6, IL-10, IL-12, and TNF-${alpha}$ in the culture supernatant of astrocytes was increased by mixed exposure with M. pneumoniae, B-16 melanoma cell and IFN-${gamma}$ than single exposure with them during experimental period. These results suggest that the inflammatory reaction of M. pneumoniae infection and B-16 melanoma cell may be augmented by mixed exposure with M. pneumoniae antigen and B-16 melanoma cell than single exposure with them.