Objective To evaluate the pre-treatment nutritional status of nasopharyngeal carcinoma NPC patients who received chemoradiotherapy and explore the relationship between malnutrition diagnosed by the Global Leadership Initiative on Malnutrition GLIM and survival outcome. Method This retrospective study was conducted in a series of 175 NPC patients treated with chemoradiotherapy at our hospitals from January 2017 to December 2021. Using a two-step method the prevalence of malnutrition in this population was investigated by GLIM criteria. Kaplan-Meier curves with Log-rank test were used to compare progress-free survival PFS and overall survival OS of malnourished and non-malnourished patients. The independent prognostic factors for NPC patients were determined by the univariate and multivariate Cox regression analysis. Result A total of 17. 1% 30 / 175 of patients had malnutrition risk according to the Nutrition Risk Screening 2002. According to GLIM criteria the prevalence of malnutrition was 25. 7% 45 / 175 in NPC patients of which 8. 6% 15 / 175 had unintentional weight loss 9. 7% 17 / 175 had low body mass index BMI and 20. 6% 36 / 175 had a decrease in muscle mass. The survival analysis indicated that the 3-year PFS rates of malnourished and non-malnourished patients were 74. 6% and 95. 3% respectively χ 2 = 15. 871 P<0. 001 . The 3-year OS rates of malnourished and non-malnourished patients were 73. 1% and 90. 5% respectively χ 2 = 7. 384 P= 0. 007 . There were significant survival differences between the two groups for PFS and OS. Malnutrition diagnosed by GLIM criteria was an independent predictor of PFS HR = 2. 335 95%CI = 1. 072-5. 084 P= 0. 031 and OS HR= 4. 810 95%CI = 1. 763-13. 127 P = 0. 002 for NPC patients. Conclusion GLIM criteria was an effective tool for nutritional assessment and survival prediction of NPC patients and it might be helpful for early detection of malnutrition and guidance of clinical intervention.