Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by itching, redness, and eczematous lesions. Interleukin 17 (IL-17) plays a crucial role in the pathogenesis of AD. Objective: This study aimed to assess the level of IL 17 in AD before and after topical corticosteroid therapy mometasone furoate (Borgasone 1% cream) and compare that to normal control. Methods: This diagnostic interventional case-control study included 30 patients with AD (Group A) and 30 healthy subjects as controls (Group B). Clinical severity scores were assessed using the SCORAD index, and subjective symptoms were evaluated using a visual analogue scale. Serum IL-17 concentrations were measured using ELISA. All patients received topical mometasone furoate cream for two weeks, and the SCORAD scores were reassessed after treatment. Results: IL-17 serum levels had significantly decreased after treatment with topical mometasone furoate when compared with before treatment (126.86±10.21 vs 238.12±23.16 pg/ml; P<0.001). Patients with AD had considerably increased IL-17 serum levels when compared with controls (238.12±23.16 vs 101.79±10.94 pg/ml; P<0.001). ROC curve revealed that cut off point 211.5 pg/ml of IL-17 had significant discriminative ability to differentiate between cases with AD and controls with area under the curve 1 (P<0.001) with 96.7% sensitivity and 100% specificity. Conclusions: The current investigation demonstrated a notable increase in the serum levels of IL-17 among individuals diagnosed with acute and subacute atopic dermatitis, as compared to the control group. Moreover, the topical mometasone furoate administration exhibited a substantial reduction in IL-17 serum levels in AD patients