Survivin is a protein that inhibits apoptosis and regulates cell division. Survivin contains a baculovirus inhibitor of apoptosis repeat (BIR) protein domain that classifies it as a member of the inhibitor of apoptosis protein (IAP) family. Survivin inhibits apoptosis, via its BIR domain, by either directly or indirectly interfering with the function of caspases. Survivin is also a chromosomal passenger protein that is required for cell division. Survivin is expressed in embryonic tissues as well as in the majority of human cancers, but is not expressed in most normal adult tissues. The cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a useful diagnostic marker of cancer and a potential target for cancer treatment. Recently, there is emerging evidence that survivin is involved in tissue injury and its healing. Understanding the mechanism of survivin function can potentially allow for the development of therapeutic strategies for cancer and other diseases.