HIV-associated salivary gland disease (HIV SGD) is an AIDS defining condition associated with significant morbidity and lymphoma development in HIV-positive individuals. Understanding HIV SGD becomes increasingly important as the burden of HIV disease expands globally. The epidemiology of HIV SGD suggests the involvement of a viral opportunist in its pathogenesis. Based on this and on histologic correlates we hypothesized that HIV SGD is a manifestation of DNA tumor virus infection/reactivation during immunosuppression. Analysis of HIV SGD lesions determined that while herpesviral gene products were not consistently detected in HIV SGD, polyomavirus nucleic acids and antigens were detected. The subcellular localization of the viral-oncoprotein in HIV SGD was similar to that in a mouse model of polyomavirus-associated salivary gland disease. In HIV SGD the polyomavirus oncoprotein, T-antigen, was consistently co-localized with p53 implicating the deregulation of this tumor suppressor in the HIV SGD pathogenesis. Collectively, these studies underscore the potential for polyomaviruses to be key etiologic agents in HIV SGD development.