As most of novel bio-markers that identify the severity of acute exacerbation in COPD, are time consuming and expensive, there is a need to use more simple tests. The Neutrophil-lymphocyte ratio is a rapid, easy and cost-effective method derived from routine complete blood count tests in clinical practice. The NLR could be an important marker that assess inﬂammatory status in patients with COPD and could identify early, acute exacerbation. However, this bio marker has not been widely used in the diagnosis of AECOPD.