Abstract： Objective To re-evaluate the prognostic value of the 6th edition of UICC/AJCC staging system in patients with nasopharyngeal carcinoma (NPC) treated with intensity-medulated radiation therapy (IMRT). Methods From February 2001 to March 2007, Clinical data of 570 NPC patients initially treated with IMRT in Cancer Center of Sun yat-sen University were reviewed and the long-term survival was analyzed according to T, N and overall stages. Results The median follow-up was 42 months. 184 patients were followed up to 5 years. The 5-year local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) and overall survival (OS) of the whole group were 93. 0%, 85.4% and 83. 3% ,respectively. No statistically significant difference of LRFS was detected between the either two of stage T_1, T_(2a) and T_(2b)(100%, 100% and 94. 5% ;T_1 vs. T_(2b), χ~2 = 1.92, P =0. 166 ;T_(2a) vs. T_(2b), χ~2= 0. 35, P =0. 555), stage T_(2b) and T_3 (94. 5% and 91.3% ;χ~2 = 2. 62, P = 0. 106), or stage T_3 and T_4 (91.3% and 89. 5% ; χ~2 = 1.55, P =0. 214). The 5-year DMFS of stage N_2 was similar with stage N_1 or stage N_3(80. 2%, 86. 2% and 61. 4% ; N_2 vs. N_1, χ~2=2.22, P=0.136;N_2 vs. N_3, χ~2= 1.92, P=0.165). No statistically significant difference of 5-year OS was observed among stage Ⅰ , Ⅱ_a and Ⅱ_b(91.7%, 100% and 95. 3% ; Ⅰ vs. Ⅱ_b χ~2 =0.32, P=0.574;Ⅱ_a vs. Ⅱ_b,χ~2-0.25, P=0.617), or between Ⅳ. And Ⅳ_b(67.9% and 75. 0% ;χ~2 = 0.25, P = 0. 616). Conclusions The 6th edition of UICC/AJCC staging system shows poor predictive value for the long-term survival of NPC patients treated with IMRT.