Background : Nowadays a lot of research is based on natural substances or materials world wide since many kinds of side effects are accompanied by anti tumor chemotherapy. In Chinese medicine, Dioscorea bulbifera L is widely used to treat many kinds of cancer, but in Korea it is rarely used. Therefore, we need to scientifically identify anti tumor effects of Dioscorea bulbifera L. Objective : We aimed to identify anti tumor effects of Dioscorea bulbifera L on the stomach cancer cells through molecular biological methods. Materials & Methods : We used AGS, a stomach cancer cell from American Type Culture Collection. We injected the boiled extract of Dioscorea bulbifera L 5 ul(sample 1), 10ul(sample 2) to cultured media(ml) for 0,6,12,18,24 hours. We measured the killing effect on stomach cancer cells through Tryphan blue exclusion test and suppressive effect on viability of stomach cancer cells via MTT assay. Results : Tryphan blue exclusion test showed that each test group killed more stomach cancer cells than the controlled group with a dosage-dependent, but not significantly. MTT assay showed that each test group had a more suppressive effect on viability of stomach cancer cells than the controlled group without a dosage-independent, but not significantly. The cell cycle analysis via flow cytometry showed that the test group extended cell cycle, and there was no peak in M phase, the number of sub G1, G0, G1 phase cells increased a little, but not significantly. Conclusion : This experiment showed that Dioscorea bulbifera L. has an anti-tumor effect, but not significantly. This is in vitro experiment and basic experiment on Dioscorea bulbifera L. We hope more progressive researches on Dioscorea bulbifera L. will be conducted and its anti tumor will be more accurately identified.