Chronic active Epstein-Barr virus infection manifests as a combination of persistent infectious mononucleosis-like symptoms and high viral load in apparently immunocompetent patients. It is closely related to Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis. These 2 abnormal Epstein-Barr virus-associated diseases are seldom reported in individuals other than Japanese children and adolescents. We report a series of 2 adult non-Japanese patients with fatal chronic active Epstein-Barr virus and 1 adult non-Japanese patient with Epstein-Barr virus hemophagocytic lymphohistiocytosis and discuss its pathogenesis and treatment options.