Using the digoxin labelled probes and DNA-RNA in-situ hybridization technique, the expression of C-erbB-2 and EGFR mRNA in routine paraffin sections of 30 human nasopharyngeal carcinomas (NPC), 20 pericarcinomatous tissues (PCT) and 16 chronic inflammatory mucosae. The results showed the positive rates of C-erbB-2 and EGFR mRNA expression were 86.7%, 83.3% respectively in NPC and 80.0%, 70.0% in PCT, while those in chronic inflammatory mucosae were no detected. Co-expression of these two genes occurred in 83.3% of NPC and 70.0% of PCT. In the PCT, the positive rates of C-erbB-2 and EGFR mRNA in the atypic hyperplasia were higher than that in the simple hyperplasia, the amount of the positive cells of these two genes increased steadily in the mild, moderate and severe dysplasia and diffused from basal lamina of epithelium to the whole epithelium. The results suggest that the activation of C-erbB-2 and EGFR genes is an early event and play a synergic role in the carcinogenesis of NPC and examination of their expression is helpful in early diagnosis.