Recent years have seen extensive growth in the understanding of the role(s) of the various PKC isozymes and novel receptors for the phorbol ester tumor promoters. The PKC family of serine-threonine kinases is an important regulator of signaling cascades that control cell proliferation and death, and therefore represent targets for cancer therapy. While past interests have focused on PKC-selective inhibitors, more recently, intensive research has been underway for selective activators and inhibitors for each individual PKC isozyme. In the past few years a large number of PKC activators and inhibitors with potential as anticancer agents have been developed. A number of these compounds are already in Phase II clinical testing. As a new generation of cancer chemotherapeutic agents are designed, developed and put through a series of rigorous clinical trials, we can anticipate achieving exquisite control over PKCmediated regulatory pathways, leading ultimately to a greater understanding of different cancers.