Purpose: To analyze the clinical outcomes of nasopharyngeal carcinoma (NPC) patients with post-radiation nasopharyngeal necrosis (PRNN) and construct a new risk classification system for predicting survival of PRNN. Methods: A total of 276 patients with PRNN were consecutively enrolled. Complete magnetic resonance (MR) images of the nasopharynx and neck were available for all patients and were used to assess nasopharyngeal necrosis status. After 2010, patients with PRNN were initially treated by radical endoscopic necrectomy followed by reconstruction with nasal flap (ENNF). Results: The 1-year and 2-year overall survival (OS) was 65.0% and 51.6%, respectively. Three variables affected survival: osteoradionecrosis, re-irradiation, and internal carotid artery (ICA) exposure, and only two variables were found to be independent prognostic factors: re-irradiation (hazard ratio [HR] 1.75, P = 0.001) and internal carotid artery (ICA) exposure (hazard ratio [HR] 1.80, P = 0.001). These two variables were combined to create a new risk classification system for PRNN. 131 (47.5%), 110 (39.9%), and 35 (12.7%) patients were classified into low-, intermediate-and high-risk group, with the 2-year OS rates of 64.8%, 45.1%, and 22.5%, respectively (P < 0.001). ENNF was associated with a better OS in these three group patients compared with conservative management with statistical or marginal statistical significance (2-year OS low-risk group, 90.9% vs 61.1%, p = 0.081; intermediate-risk group: 100% vs 37.8%, P = 0.001; and high-risk group, 57.1% vs 20.8%, p = 0.066). Conclusion: The new risk classification system provides accurate estimates of prognosis. ENNF surgery may lead to better survival outcome than conservative management in PRNN patients. (C) 2017 Elsevier Ltd. All rights reserved.