Abstract: Objective To investigate the effect of excision repair cross complementation group 1（ERCC1） expression on response to cisplatin-based chemoradiotherapy in locally advanced nasopharyngeal cancer（NPC） patients. MethodsIn a retrospective study, 205 patients with locally advanced NPC from January 2001 to January 2009 were divided into treatment sensitivity group and treatment resistant group. Immunohistochemistry was used to assess ERCC1 expression in NPC tissue. The relationships between ERCC1 expression and response rate（RR）， 5-year disease free survival rate and overall survival rate were analyzed. ResultsOf 205 NPC patients， ERCC1were highly expressed in 110 cases and lowly expressed in 95 cases. The RR in NPC patients with high ERCC1 expression（97.3％） and those with low ERCC1 expression（100.0％） had no statistical difference. The low expression and high expression rate of ERCC1 in the treatment sensitive group were 61.4％ and 386％，significantly different from 35.9％ and 64.1％ in the treatmentresistant group（P=0.000）. The median overall survival in patients with low ERCC1expression and high ERCC1expression were 61.3 and 49.7 months（P=0.013）. The 5-year disease free survival rate were 61.5％ and 36.2％（P=0.054）and the 5-year overall survival rate were 63.4％ and 38.5％，respectively（P=0.037）. Multivariate analysis showes the ERCC1 expression，stage and PS status were independent predictors for overall survival. ConclusionERCC1 expression might be a useful predictive marker of clinical effect in patients with locally advanced NPC receiving cisplatin-based concurrent chemoradiotheapy.