Specific antibody responses against the Epstein-Barr virus-coded nuclear antigen2 (EBNA2) were evaluated. Thirty-five sera from pretreatment patients of nasopharyngeal carcinoma (NPC) and 12 from healthy adults were tested. Although the anti-EBNA2 response did not show any correlation with T stage, overall stage, or histopathology, it showed a correlation with the N stage of the disease. In a serological follow-up study, 17 (85%) of 20 patients showed a correlation on the change of antibody levels to EBNA2 and clinical progression. This suggests that EBNA2 serology might represent a useful marker relative to tumor status.