From 1968 to 1973, 793 cases of nasopharyngeal malignancies in Japan were examined histopathologically and immunologically. The majority of the carcinomas were undifferentiated squamous cell carcinomas, including transitional cell carcinoma and lymphoepithelioma. These findings correspond well with those of other countries. There were more well differentiated carcinomas in the old than in the young age groups. The positive rate (80%) and the geometric mean of the anti-VCA-antibody titers (more than 1:750) were remarkably high in the lymphoepithelioma group. These two factors seem to be very important to the study of oncogenesis of nasopharyngeal carcinoma (NPC). The relationship between subpopulations of peripheral lymphocytes in NPC and histopathological classification was investigated. The lymphoepithelioma group had a higher proportion of B cells (complement receptor cells) to T cells (erythrocyte rosette forming cells) than healthy persons throughout the clinical course, and its prognosis was not good.