AimElevated neutrophil-to-lymphocyte ratio (NLR) has been demonstrated to be a poor prognostic factor in multiple types of malignancies, whereas the effect of NLR on the prognosis of epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC) patients treated with first-line EGFR tyrosine kinase inhibitors (TKIs) is not fully addressed. Methods81 metastatic NSCLC patients harboring EGFR mutation treated with first-line EGFR TKIs were retrospectively included. The associations between baseline clinical characteristics, including NLR, and tumor response, progression and survival were investigated. ResultsElevated NLR (3.5) was observed in 33 of 81 patients. The progression-free and overall survival of the patients with increased NLR was significantly worse than that of the patients with decreased NLR (8.20 vs 10.60 months, P<0.001 and 17.20 vs 23.20 months, P<0.001, respectively). Elevated NLR was confirmed to be an independent prognostic factor for worse progression-free and overall survival in Cox multivariate analysis. ConclusionElevated NLR is likely to be associated with poor outcome in EGFR-mutated advanced NSCLC patients treated with first-line EGFR TKIs.