Background: Asthma is a chronic inflammatory condition affects all age groups, but it peaks in pediatrics. T2-mediated immunity has long been thought to be the pathophysiological mechanism of asthma. Also, the disease is associated with inflammatory mechanism, so the identification of a reliable inflammatory biomarker for diagnosing asthma and assessment of the disease severity is a great importance. Aim of the Study: Evaluate the role of neutrophils to lymphocytes ratio as a biomarker in asthma severity and control. Methods: This case control study was carried out on 44 asthmatic children and 44 healthy controls. The children who were included underwent a comprehensive evaluation that included obtaining a thorough clinical history, conducting a full clinical examination to determine the severity of their asthma, and looking for any atopic diseases. Assessment of the different laboratory parameters was conducted with determination of the neutrophil lymphocyte ratio. Results: The neutrophil/lymphocytes ratio was statistically significantly higher in the asthmatic cases as compared to the controls (P < 0.001). The best cutoff point of Neutrophil/lymphocytes ratio to identify cases with asthma from control was > 1.75 with 79.5% sensitivity and 75.9 specificity. The AUC was 0.826 and the value was statistically significant. Cases with severe asthma and cases with severely uncontrolled disease showed higher level of NLR compared to the cases with mild and moderate asthma and compared to cases with controlled asthma respectively. Conclusions: Neutrophil/lymphocytes ratio could be used as non-invasive diagnostic biomarker for diagnosing asthma and is strongly correlated with degree of disease severity.