Making use of a new histologic classification developed by the World Health Organization, we reviewed 177 US and 30 foreign cases of nasopharyngeal carcinoma (NPC). Tumors of US whites included undifferentiated, squamous cell, and non-keratinizing carcinomas, while US blacks had undifferentiated carcinomas only. There were no significant histological differences between the tumors from US- and foreign-born patients. White male subjects from the United States had a braod age distribution, with a peak in the 60- to 69-year range. Black subjects from the United States, on the other hand, had a prominent incidence peak in the 10- to 19-year age range. These pathologic and age-related differences may provide clues as to those factors involved in the cause and pathogenesis of NPC.