Abstract: Objective To compare the differences of the proportions of CD4+／CD25+and CD28+／TCR+T cells in peripheral blood between patients with advanced nasopharyngeal carcinoma（NPC） and healthy volunteers， and explore the potential significance of the aberrant lymphocyte subpopulations of T cells for prognosis in NPC patients. Methods Twenty-nine healthy volunteers（control group） and 53 patients with advanced NPC（NPC group） were recruited. The peripheral venous blood samples were harvested and the peripheral lymphocytes were isolated and collected by ficollhypaque density centrifugation. The proportions of CD4+／CD25+ and CD28+／TCR+T cells were measured by flow cytometry. The relationship between the aberrant proportions of these T cells and the risk of relapse in NPC patients was analyzed according to the followup data of 18 months after chemoradiotherapy. Results The proportion of CD4+／CD25+T cells in NPC group was（10.6±2.7）％， higher than（7.7±2.0）% in control group（P＜0.05）， whereas the proportion of CD28+／TCR+T cells in NPC group was（1.9±0.6）％， lower than（2.9±1.0）% in control group（P＜0.05）. According to the 95％ confidence interval of the proportions of CD4+／CD25+and CD28+／TCR+T cells in control group， the NPC group was divided into normal（≤8.5％） and elevated（＞8.5％） CD4+／CD25+T subgroup or normal（≥2.5％） and reduced（＜2.5％） CD28+／TCR+T subgroup. The relapse rate of elevated CD4+／CD25+T subgroup within 18 months after treatment was 32.1%, higher than 87% of normal subgroup with significant difference（P＜005）. No difference was observed between subgroups of CD28+／TCR+T. Conclusion The proportion of CD4+／CD25+T cells is a potential prognostic factor for the risk of relapse in patients with advanced NPC.