Objective To explore the feasibility of employing a risk category system in evaluating the treatment outcome of locoregionally advanced nasopharyngeal carcinoma (NPC) treated by intensitymodulated radiation therapy (IMRT) alone,and offering evidence for relevant perspective studies.Methods Totally 185 locoregionally advanced NPC patients were divided into high-risk and low-risk groups for evaluation and comparison.The patients who met at least one of the following criteria were defined as high-risk group and others as low-risk group:GTVnx ＞ 30 cm3;Clinical stage T4N2M0;multiple neck node metastases with 1 node size ＞4 cm,and N3 with any T stage.Results With a median follow up of 110.9 months (6.7-152.4 months),the 5-year overall survival,locoregional relapse-free survival,distant metastasis-free survival for the high-risk group vs.the low-risk group were 61.0％ vs.90.5％ (x2 =30.298,P＜0.05),78.3％ vs.91.5％ (x2 =6.352,P＜0.05)and 71.6％ vs.92.0％ (x2 =16.346,P ＜0.05).Conclusions As a simple and practicable method,the risk category system is helpful for discriminating locoregionally advanced nasopharyngeal carcinoma with different risk-group of treatment failure and in further perspective clinical research.