Chronic obstructive pulmonary disease (COPD) is a disabling condition that is characterized by ir reversible airflow limitation and inflammation. Exacerbated COPD is a common cause of hospitalization and death. Aims: to determine the significance of neutrophil-lymphocyte ratio (NLR) in exacerbated COPD patients. This is a cross sectional study that included outpatients with stable and ER, inpatients exacerbated COPD. The study included 60 patients with exacerbated COPD, 60 patients with stable COPD and 60 age- and gender matched apparently healthy subjects. Blood samples were collected from each participant, and NRL was calculated for complete blood count. Total leukocyte and neutrophil count but not lymphocyte count were significantly higher in COPD patients than controls. Exacerbated patients displayed higher NLR (4.47±1.9) than either stable patients (3.19± 1.71) or controls (1.81±0.65) with highly significant differences between the three groups. In the context of discrimination between exacerbated patients and controls, the area under the curve of receiver operating characteristics curve was 0.942, 95%CI= 0.905-0.979, p<0.001. The sensitivity and specificity of the test at cut off values of NLR= 2.41 were 0.88 and 0.82 respectively, indicating a very good diagnostic value. The NLR demonstrated a a negative significant correlation with forced expiratory volume during the first second (r= -0.269, p= 0.038). Exacerbated COPD patients had higher NLR compared with stable patients and healthy controls. The NLR has a very good diagnostic value of NLR especially in the context of discrimination between exacerbated patients and healthy controls.