A case of undifferentiated carcinoma of the salivary gland occurring in the parotid gland of a southern Chinese was reported. Tumour cells showed immunofluorescence for Epstein-Barr virus (EBV)-associated nuclear antigen, and DNA hybridization demonstrated the presence of EBV-DNA in tumour tissue. The findings in this case, together with previous reports, suggest a causal relationship between EBV and salivary gland carcinoma. The relationships between EBV and undifferentiated epithelial tumours of the salivary glands, nasopharynx and thymus are also discussed.