Serum neutrophil-to-lymphocytes ratio (NLR) is a potential predictive and prognostic marker in head and neck cancers. This study aimed to determine the role of pretreatment serum NLR in patients with hypopharyngeal cancer (HPC) treated with definitive chemoradiotherapy. We retrospectively investigated the correlation between clinicopathological parameters and NLR status and analysed its impact on therapeutic response and survival. A total of 120 patients treated at a single institution between 2009 and 2015 were included. The median follow-up time was 24.1 months. High NLR (NLR ≥ 4) was associated with advanced T classification (p = 0.01*) and advanced stage (p = 0.02*) based on chi-square test. We also found that high pretreatment NLR was correlated with poor treatment response (HR = 2.42, 95% CI: 1.08-5.44, p = 0.03*). Pretreatment NLR was also an independent prognostic factor for progression-free survival (HR = 1.71, 95% CI: 1.01-2.90, p = 0.046*) and overall survival (HR = 1.99, 95% CI: 1.21-3.28, p = 0.01*) while correcting for known prognostic factors. Overall, these findings support that NLR is a potential biomarker for host response to tumour aggressiveness, therapeutic response to chemoradiotherapy and survival in HPC patients. This study is limited by its retrospective nature and further validation is warranted.