Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative motor neuron disease and remains misunderstood with difficult diagnosis and prognosis. The implication of the immune system is recognized in ALS pathophysiology, hence the interest in leucocytes count as lymphocytes and neutrophils. The neutrophil to lymphocyte ratio (NLR) has recently been used as a prognosis factor to assess the progression of ALS. Thus, the aim of this study was to analyze the evolution of the NLR during disease evolution in a French cohort of ALS patients and its relation with survival. Clinical parameters and NLR were collected in ALS patients followed at the University Hospital of Tours (France). ALS patients were subdivided into three groups in regard to their NLR value at inclusion: group 1 (NLR < 2); group 2 (NLR: 2-3); group 3 (NLR > 3). Comparison of qualitative and quantitative clinical and biological variables between NLR groups was performed. Then Cox-regressions were carried out to determine the association of NLR with survival. We observed a significant correlation of NLR with ALSFRS-r score (p<0.0001) and with vital forced capacity (p=0.0004) at inclusion. We observed that increased NLR at diagnosis is associated with decreased ALS patients’ survival.