Survivin has multiple functions including cytoprotection, inhibition of cell death, and cell-cycle regulation, especially at the mitotic process stage, all of which favor cancer survival. Many studies on clinical specimens have shown that survivin expression is invariably up-regulated in human cancers and is associated with resistance to chemotherapy or radiation therapy, and linked to poor prognosis, suggesting that cancer cells survive with survivin. It is also reported that survivin inhibition, alone or in combination with the other therapies, induces or enhances apoptosis and mitotic catastrophe in tumor cells. Moreover, certain antitumor agents can reduce survivin expression. These findings suggest that survivin may be a promising molecular target against human malignancies. (Cancer Sci 2008; 99: 1709–1714)