ABSTRACT Background The purpose of this study was to assess the efficacy and toxicities of reirradiation using intensity‐modulated radiotherapy (IMRT) in patients with locally advanced recurrent nasopharyngeal carcinoma (NPC). Methods Thirty‐eight patients with consecutive rT3 to rT4 NPC treated between 2005 and 2013 were retrospectively analyzed. Results The 3‐year overall survival (OS), progression‐free survival (PFS), and local control rate were 47.2%, 17.5%, and 44.3%, respectively. Gross target volume (GTV) D95, GTV D50, and age were all important prognostic factors for OS and PFS, but only GTV D95 was an important determinant for local control. A total of 73.7% patients experienced ≥1 grade 3 late toxicities and 3 patients died of massive epistaxis. Temporal lobe necrosis (TLN) developed sooner with a higher total biological equivalent dose. Conclusion Adequate tumor dose coverage was important for treating rT3 to rT4 NPC. Although late complications were common, treatment‐related mortality was solely vascular in nature. Dose constraints of neurologic structures for reirradiation should be revised with the latest information on late toxicities. © 2016 Wiley Periodicals, Inc. Head Neck 39: 533–540, 2017