Background and objective: Asthma is not a single disease but, rather, a heterogeneous inflammatory disorder with various pathogenic mechanisms. A key element of severe asthma (SA) has been stated to be eosinophilic inflammation (EI). However, there is no serum biomarker that can reliably predict EI in SA. In this regard, the present study was carried out to evaluate the biomarkers of allergic asthma (AA), and their association with serum parameters. Methods: The present cohort study consisted of 66 AA and 61 healthy controls (HC) from January 2017 to November 2018. Data on variables, like all types of leukocyte cells, total and specific serum IgE, ECP, tryptase, IL-18, CD-20, and FEV1 were obtained. For comparison between the unpaired variables, the Mann-Whitney U test, χ2 test, and Kruskal Wallis H test was used. Results: Symptoms (cough, wheezes, dyspnea) and family history were found as significant indicators for AA (p less than 0.05). The AA and HC were significantly different in terms of blood and serum parameters (i.e., WBC, lymphocyte, monocyte, neutrophil, eosinophil, basophil, total IgE, external counterpulsation (ECP), tryptase, IL-18, and CD-20) (p less than 0.05); therefore, these factors might be reliable indicators of AA. Also, most of the biomarkers were significantly correlated with the serum parameters, which reveal the reliability of these variables as indicators of AA. Conclusion: All types of leukocyte cells were found as reliable biomarkers to diagnose AA patients from HC. Also, FEV1%, Total WBC, and serum total IgE, ECP, Tryptase, IL-18, and CD-20 were found as reliable biomarkers for the severity of AA.