Objective : The purpose of this study was to investigate the effects of Armillaria mellea extract (AME) on immune modulation focused on anti-cancer activity. Methods : To prove the effects of AME, we performed NO assay, NK cytotoxicity assay and RT-PCR of cytokine related with macrophage and NK cell activity. Results : AME increased NO production produced by macrophages in part. AME also enhanced the NK cell activities in destroying target cells (YAC-1 cells). AME up-regulated gene expression of IL-l, iNOS, TNF-a in RAW 264.7 cells and IL-l, IL-2, IFN-(equation omitted), TNF-a in splenocytes, respectively. Conclusion : From the above results, we assumed that AME is a potential drug for anti-cancer by activation of the macrophages and NK cells.