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<p><b>Background:</b> Adoptive immunotherapy with EBV-specific CTLs (EBV-CTL) has been used to treat EBV-associated nasopharyngeal carcinoma (NPC) but only a fraction of the patients shows noticeable clinical response.</p><p><b>Patients and Methods: </b>Sixty-seven newly diagnosed NPC patients from 2005 to 2007 and 21 healthy donors were collected. Immunological parameters and immune function of PBMCs and EBV-CTL were analyzed by flow cytometer analysis (FACS) and ⁵¹Cr releasing experiment; Molecular characteristics on NPC tumor cells were investigated by immunochemical staining and statistic analysis.</p><p><b>Results:</b> NPC patients can be classified into two groups based on the percentage of CD3⁺ T cells in peripheral blood before accepted any treatment, (&#62;52.6%, mean-2SE from healthy controls, NPC Group 1; &#60;52.6%, NPC Group 2). The patients in Group 2 showed a significant decrease of CD3⁺CD8⁺ T-cells, CD3⁺CD4⁺ T-cells and CD3⁺CD45RO⁺ memory T cells, and increase of CD3^-CD16⁺ NK cells compared to Group 1 patients and healthy controls (P&#60;0.001). EBV-specific T cell responses, were weaker in this group of patients and their tumor cells expressed lower levels of the EBV encoded latent membrane protein (LMP)-1 and HLA class II protein compared with the patients of NPC Group 1 (P&#60;0.05) .</p><p><b>Conclusion:</b> These findings demonstrate that NPC patients could be distinguished on the basis of their immune status which will affect the efficacy of EBV-CTL immunotherapy.</p>