Objective To analyze the long-term outcome of nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT) with reduced clinical target volume (CTV)and to provide a basis for the application of reduced-volume IMRT in the treatment of NPC. MethodsBetween November 2003 and April 2007, 413 patients with NPC were treated with IMRT according our institutional protocol. The median age was 45 years;the patients included 311 males and 102 females. Of all patients, 3(0.7%) had stage Ⅰ NPC, 66(16%) had stage Ⅱ NPC, 235(56.9%) had stage Ⅲ NPC, 78(18.9%) had stage Ⅳ_a NPC, and 31(7.5%) had stage Ⅳ_b NPC, according to the 6^th edition of AJCC staging system. IMRT was delivered as follows:GTV 66.00—69.75 Gy/30—33 f;CTV-1 60.00—66.65 Gy/30—33 f;CTV-2/CTV-N 54.0—55.8 Gy/30—33 f. A total of 336 patients received cisplatin-based chemotherapy in addition to IMRT. Results The follow-up rate was 100%. With a median follow-up of 72 months, the 5-year overall survival (OS), local control, loco-regional recurrence-free survival, distant metastasis-free survival (DMFS), and disease-free survival rates were 80%, 93%, 96%, 81%, and 75%, respectively. The multivariate analysis revealed that T stage, N stage, and age were independent prognostic factors for OS (P=0.001,0.001,0.002);T stage and N stage were independent prognostic factors for DMFS (P=0.000,0.001). Among patients with stage Ⅲ and IV NPC, the 5-year OS rate was nonsignificantly higher in those treated with induction chemotherapy than in those not treated with induction chemotherapy (78% vs. 68%, P=0.053), but the 5-year DMFS rate was significantly lower in those treated with adjuvant chemotherapy than in those not treated with adjuvant chemotherapy (65% vs. 83%, P=0.003). Conclusions IMRT with reduced CTV is safe and reliable and can lead to a good long-term outcome in patients with NPC.