Amplification of the c-erbB-2 gene has been associated with poor prognosis in different types of cancer. However, there are no data an the c-erbB-2 expression levels in nasopharyngeal cancer. In this study, amplification of the gene has been investigated in the tumor tissue of patients with nasopharyngeal cancer by competitive polymerase chain reaction c-ErbB-2 amplification was observed in 43.3% of the patients. The increase in the gene copy number correlated with the T stage. No correlation was found with lymph node involvement, histologic grade, differentiation, presence of metastases, or age and sex. We conclude that c-erbB-2 amplification may contribute to the pathogenesis of nasopharyngeal cancer. Our report is the first study investigating the expression of the c-erbB-2 gene in nasopharyngeal cancer at the DNA level.