Objective: This study is aimed to identify the antitumor effect of bone marrow stromal cells (BMSCs) in co-culture with C6 glioma and to elucidate the mechanism of this antitumor effect by expression of nerve growht factor (NGF) and tumor necrosis gactor (TNF) Methods: The BMSCs were harvested from Fischer 344 male rat (200~300g) femur aseptically. These BMSCs were CD34 negative and CD45 weakly positive, but CD90 and Sca-1 were strongly positive by flowcytometry. These cells were then Differentiated to adipocyte and C6 glioma cells were co-cultured with BMSCs (5000:5000 per cm²). At 4 day after seeding, co-cultured cells were performed protein extraction by lysis buffer for NGF and TNF enzymelinked immunosorbent assay (ELISA). At 7 day after seeding, co-cultured cells were taken a picture by microscope and BMSCs were transplanted into the rat glioma model. Results: The proliferation rate of co-cultured C6 glioma with BMSCs that compared with only C6 glioma group was decreased. Also, transplanted BMSCs influenced the decrease of tumor volume in vivo. TNF of the co-cultured group (24.29 ±4.07 pg/ml) showed stronger expression than that of the only BMSC group (3.99±0.46 pg/ml, p<0.05) whereas expression of TNF in the only C6 glioma group was no detcted. NGF of the co-cultured group (79.09±4.83 pg/ml) expressed stronger than that  of the only C6 glioma group (57.35±0.32 pg/ml, p<0.05). Also, in vivo studies, NGF and TNF of C6 glioma and BMSCs group (190.30±8.06 and 137.74±10.16pg/ml) expressed stronger than that of the C6 glioma group (140.65±6.15 and 104.80±0.17 pg/ml, p<0.05). Conclusions: These results indicate that BMSCs seem to have an inhibitory effect  for proliferation of C6 glioma and this mechanism was positively associated with TNFexpression of BMCs