The author classified 38 cases of malignant lymphoma involving the skin primarily or secondarily by the new WHO classification with minor modifications and carried out RNA in situ hybridization and/or polymerase chain reaction (PCR) to investigate the role of Epstein-Barr virus (EBV). A case was follicular lymphoma of B cell origin and 37 cases were malignant lymphomas of T cell origin, including 15 cases of Mycosis fungoides/Sezary syndrome, five cases of subcutaneous panniculitis-like T cell lymphomas, a case of anaplastic large cell lymphoma, and four cases of primary cutaneous CD30 T cell lymphoproliferative disorders. There were eight cases of unspecified peripheral T cell lymphomas, in which four cases were composed of medium-sized cells, three cases of large cells, and a case of lymphoepithelioid cells. Four cases of nasal and nasal type NK/T cell lymphomas and three cases of unspecified peripheral T cell lymphomas showed EBV genome. The nasal and nasal type NK/T cell lymphomas, especially those involving the nasal cavity, showed close association with the EBV infection.