The elimination of a tumor cell population by exposure of the tumor to lethal doses of drugs or radiation is a well-established strategy in cancer therapy. Although better cytotoxic chemo-and radiotherapy regimens, coupled with the discovery of new chemotherapeutics, will continue to improve the effectiveness of such treatments, recent discoveries in the field of cell death promise to have a major impact in this area. Because apoptosis is an active process under molecular control, information concerning the regulation and execution of this type of cell death should lead to the development of more effective means of eliminating malignant cell populations. In addition, discovering how normal controls on apoptosis can fail should also improve our understanding of how tumors develop.