Objective: To study the prognostic value of leukocyte increase in a retrospective cohort of locally advanced head and neck squamous cell carcinoma (HNSCC) patients receiving definitive concurrent cisplatin and radiation. Materials and methods: Clinical records of consecutive previously untreated locally advanced HNSCC patients treated in our Institution between March 2006 and October 2012 by concurrent cisplatin (100 mg/m2, every 3 weeks) and radiation (70 Gy in 7 weeks) were collected. The prognostic value of pretreatment leukocyte increase was examined, with focus on patterns of relapse and survival. Leukocytosis and neutrophilia were defined as a leukocyte count or a neutrophils count exceeding 10 and 7.5 G/L, respectively. Results: We identified 193 patients, all treated with concurrent cisplatin-based chemoradiotherapy. Respectively 24% and 20% patients displayed baseline leukocytosis or neutrophilia. Mean leukocyte count were significantly more elevated in current smokers, patients with performance status (PS) >0, T4 and less in HPV + tumor. The 5-year actuarial overall survival (OS) and progression-free survival (PFS) were 56% and 51% respectively. In univariate analysis, both leukocytosis and neutrophilia were strongly associated with worse OS and PFS (p