Cancer cells undergo mitosis frequently, and many mitotic regulators are aberrantly expressed in these cells. Members of the Aurora family of serine/threonine kinases are expressed during mitosis and carry out vital functions in chromosome alignment, segregation and cytokinesis. Here we review the functions of Aurora-B kinases in mitosis and summarize the current literature on Aurora-B kinase inhibitors. In the process of developing these inhibitors as anticancer drugs, the Aurora kinase inhibitors have also helped to advance our understanding of the role of Aurora kinases in mitosis. The mechanism of action and structure-activity relationship of a selective Aurora-B inhibitor are also discussed. The future may see mechanism guided design of chemotherapy combinations that include these cell-cycle phase-specific drugs. The therapeutic potential of Aurora-B inhibitors is promising.