Aim: The exact immunopathogenesis of Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) remains unclear. The aim of the present study was to assess the expression of CD4, CD8, and MHC class I molecules in NPC. Method: Biopsies were obtained from patients with NPC as well as the Epstein Barr virus (EBV)-seronegative patients as a control. Nasopharyngeal carcinoma patients were classified using the World Health Organization (WHO) pathological assessment and clinical staging of NPC. The expression of CD4, CD8, and MHC class I in the biopsies were assessed immunohistochemically. Result: The results showed that the number of CD4 positive, CD8 positive, and MHC class I positive cells in NPC patients were higher than those in EBV-negative subjects (p<0.05). The number of these positive cells in NPC patients with WHO Type II or early clinical stage was not significantly differences with those with WHO Type III or late clinical stage, respectively (p>0.05). No statistical differences between the number of CD4 positive and CD8 positive cells in NPC patients could be found (p>0.05). Conclusion: The results of the present study suggest, therefore, that the expression of CD4, CD8 and MHC class I molecules may not be associated with the pathologic classification and clinical staging of NPC and that the CD4:CD8 ratio in nasopharyngeal carcinoma may indicate decreased functions of these infiltrating T cell subsets.