Kaposi's sarcoma‐associated herpesvirus (KSHV or HHV‐8) is linked to the etiopathogenesis of Kaposi's sarcoma, a plasmablastic variant of Castleman's disease and primary effusion lymphoma. KSHV is related to a number of non‐human primate viruses. Only a limited number of KSHV proteins are expressed in tumor cells. Here we discuss the putative role of these proteins in KSHV pathogenesis.