Two type of human herpes viruses, type 4(Epstein Barr virus, EBV) and type 8(HHV8) are known to cause malignancies. Among those, EBV is the very most popular human oncovirus. It can cause malignant lymphomas of various subtypes including Burkitt's lymphoma, opportunistic lymphomas, pyothorax-associated lymphoma, nasal T/NK cell lymphoma, Hodgkin's disease and a part of diffuse large cell lymphomas. HHV8 is a new member of human oncovirus associating with primary effusion lymphoma, a part of solid lymphoma taking diffuse large or anaplastic large cell morphology, and the Castleman's tumor. Introduction of histopathologic methodologies makes the correct diagnosis of those herpes virus-associated tumors an easy routine test.