The frequency of oropharyngeal excreters of the Epstein-Barr virus among patients with nasopharyngeal carcinoma in Hong Kong was compared with those of healthy adults in Hong Kong and California. 6 (3%) of 177 patients, 11 (12%) of 92 Hong Kong residents, and 20 (15%) of 132 Californians were excreters. The virus was detected in the nasopharyngeal secretion of only 1 of 67 patients and in 2 of 73 healthy adults. No convincing evidence for neutralizing antibody in the throat wash and nasopharyngeal secretions of the patients could be obtained. Epstein-Barr viral gene sequencing could not be detected in the throat washes from 27 patients with nasopharyngeal carcinoma, 8 patients with infectious mononucleosis, and 15 healthy adults and in the nasopharyngeal secretions of 35 patients and 17 controls. We conclude that patients with nasopharyngeal carcinoma are no more likely to be oropharyngeal or nasopharyngeal excreters of the Epstein-Barr virus than healthy adults. One possible explanation for this unexpected finding is that the virus infections in nasopharyngeal carcinoma cells are predominantly nonproductive.