Background: Adenoid hypertrophy (AH) plays an important role in chronic rhinosinusitis and chronic otits media in children. Children may frequently have recurrent upper and lower respiratory tract infection. Objectives: To assess anti leukotrienes effect on CD64 expression on surface of monocyte cells in children complaining of adenoid hypertrophy. Methodology: This study was conducted on Patients diagnosed with adenoid hypertrophy at Otorhinolaryngology Department, Benha University Hospital, Egypt during the period from February 2018 to October 2018. Sixty patients were included and they were divided into two groups: group (1) 30 Patients who did not take antileukotrienes therapy (control group), and group (2) 30 patients who had commenced antileukotrienes therapy (case group). Samples of blood were taken from all patients to measure the level of CD64 by flow cytometry at Medical Microbiology and Immunology Department, Faculty of Medicine, Benha University before and after 3 months of antileukotrienes therapy. Results: Statistical data for CD64 levels revealed that at the comparison between CD64 levels at the beginning of this study and then after 3 months in group (1) were 157.63 and 141.64 respectively. There was non significant difference (P value =0.127) while at comparison between CD64 levels pre and post treatment in group (2) the level was 157.63 and 141.64 respectively. There was a significant difference (p value =0.003). The adenoid size had three courses in the study; stationary, regressive and progressive. None of patients in the group 1 showed regressive course regarding adenoid size. In group 2, one patient showed a progressive course while most cases (22 patients) had regressive course as they were improved on treatment. There was a highly significant difference in the different categories of adenoid size between the two groups (P value< 0.0001). Conclusion: Antileukotrienes therapy might be generally associated with decreasing levels of CD64 expression on surface of monocytes that lead to decrease the adenoid size in children complaining of adenoid hypertrophy..