Over the past twenty odd years, kaposi's sarcoma has launched from being a rare pathological curiosity to a significant public health concern. This massive increase in incidence, concurrent with the aids epidemic, has sparked a tremendous amount of interest in uncovering the etiopathogenesis of this disease. Due to its striking association with hiv infection, researchers have focused on identifying a possible infectious agent as the cause of this disease. Such an agent, termed kaposi's sarcoma-associated herpes virus (kshv) was identified in 1994. In the following years, virologists have employed all of their molecular tools to characterize this new agent and its role in the pathogenesis of human disease. Indeed, these efforts have been quite fruitful. It is now known that kshv is a gammaherpesvirus, which like its relatives establishes a latent form of infection that appears to be a prerequisite for expression of a disease phenotype. The relevant disease states and the basic virology are discussed.