In an attempt to associate oropharyngeal excretion of Epstein-Barr (EB) virus with lymphoproliferative disorders other than infectious mononucleosis, we tested throat gargles collected from adult subjects for the EB virus. Nine (16%) of 55 healthy persons were positive. High EB virus-excretion rates were found among patients with active acute lymphocytic leukemia (6/6, 100%), among renal homograft recipients during the third to 12th month after transplantation (26/30, 87%), and among critically ill patients with leukemia-lymphoma (14/19, 74%). Moderately high excretion rates were found among patients with myeloma (7/16, 44%), patients with poorly differentiated lymphocytic lymphoma (5/11, 44%), critically ill patients with solid cancers (15/37, 41%), and patients with chronic myelogenous leukemia (8/21, 38%). Our data suggested that the higher than normal excretion rate is related to the basic disease process and to the general health status but not to the duration of cancer chemotherapy.