Intravascular lymphoma (IVL) is a rare neoplasm, recently included as a specific entity in the World Health Organization classification of lymphoid tumors. Most cases are of B-cell lineage; however, rare cases of T-cell phenotype have been reported. We report a human immunodeficiency virus (HIV)-positive patient who died of acute renal failure in whom IVL was identified at autopsy, predominantly involving the renal interstitial vessels. Immunohistochemical stains revealed a T-cell phenotype, which was confirmed by T-cell receptor gamma gene rearrangement studies. The lymphoma cells showed nuclear Epstein-Barr virus (EBV)-encoded RNA transcripts by in situ hybridization, suggesting that EBV might be of etiologic importance in this tumor. The predominant involvement of kidney is unusual. With effective therapy, morbidity and mortality of HIV-1 infection has been substantially reduced, and survival times have been prolonged. However, the relative risk of secondary neoplasms, especially non-Hodgkin's lymphoma (NHL), has increased. Consequently, we conclude that unique types of NHL, such as this case of IVL, may be encountered more frequently in this patient population, and that NHL should be added to the list of differential diagnostic considerations in HIV-1-positive patients who develop acute renal failure.