Survivin, a member of the inhibitor of apoptosis (IAP) family, plays an important role in drug resistance and cancer cell survival in many types of cancer. YM-155 is a novel small molecule that suppresses transactivation of survivin through direct binding to its promoter. It selectively suppresses expression of survivin and induces apoptosis in p53-deficient cancer cells in vitro at 10 nM. At concentrations up to 100 nM, YM-155 has little effect on expression levels of other IAP- or Bcl-2-related proteins. YM-155 exerts anti-tumor effects in various in vivo cancer models, including prostate, pancreatic, and lung cancer.