A 56-year-old Japanese man was admitted to the hospital with a large mass in his right axilla. Histological investigation revealed that it was a Burkitt's lymphoma. Ultrastructures of the tumor cells showed immature lymphoid features with frequent lipid droplets within the cytoplasms. Virological studies before the treatment revealed that the lymphoma was closely related to EB virus infection, being positive for EBNA (more than 95% of all tumor cells) and IgG antibodies to VCA (X 5,120), EA (X 640), and EBNA (X 160). The tumor cells exhibited low levels of cytoplasmic IgM and other properties of B cells. They were positively stained with L26, L27, Leu 14, and HLA-DR MAb. In cultured tumor cells, L25 and CALLA antigens were demonstrated, but no surface Ig was shown. In contrast, the tumor cells were negative for T cell markers including AcP, E-receptor, and Leu 1, 2, and 3. Cytogenetic studies demonstrated that the karyotype of the tumor cells was 46, XY, dup (1q), t(2;8)/46, X, -Y, t(2;8), +mar. VEMP therapy was immediately conducted. However, following a two-month partial remission, a relapse with bone marrow infiltration occurred. Thus, a case of Japanese Burkitt's lymphoma with EBNA (+) and t(2;8) properties is described, and the relationships among primary sites, phenotypes, and genotypes are discussed.