To evaluate long-term outcome in locoregionally advanced nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy. Between January 2006 and August 2008, 249 patients with stage III-IVb NPC were treated by IMRT plus concurrent chemotherapy in this multicenter prospective study. With a mean follow-up of 54.1 months, the 5-year actuarial rates of overall survival (OS), local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), and distant metastasis-free survival (DMFS) were 78.4%, 86.8%, 88.4%, 78.0%, respectively. There were 29 local recurrences, 25 regional recurrences and 52 distant metastases, respectively. Distant metastasis is the main cause of treatment failure. N-stage was an independent prognostic factor for LRFS, RRFS, DMFS and OS. Acute toxicity ⩾grade III mainly consisted of mucositis (34.9%), neutropenia (11.2%), xerostomia (5.6%), and dermatitis (5.2%). The main documented late toxicity was xerostomia, and the severity of xerostomia decreased over time. At 24 months after treatment, 13.2% of patients had grade 2 xerostomia, and none had grade 3 or 4 xerostomia. IMRT with concurrent cisplatin chemotherapy resulted in encouraging rates of local and distant control and overall survival with acceptable rates of acute and limited rates of late toxicity in patients with locoregionally advanced NPC. Distant metastasis remained the main cause of failure. More effective systemic therapy should be explored for patients with advanced N-stage. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.