Four cases of undifferentiated nasopharyngeal carcinomas (NPC) (grade III-IV) in patients of Indian origin were investigated for specific chromosome markers and evidence of Epstein-Barr virus (EBV) positivity. Abnormalities involving chromosome #3, like del (3) (p24-pter) and 3q+(q27-qter) were found in these patients, similar to earlier reports in patients of Chinese and Kenyan origin2,4,13 who however were EBV positive, unlike the patients in this study who were EBV negative. Implications of the cytogenetic and serological data in Indian patients with NPC, available for the first time, may throw some light on the etiology of the disease in this ethnic group where nasopharyngeal carcinoma is also endemic.