Objectives: To evaluate the role of combined therapy using montelukast and intranasal mometasone furoate compared to intranasal mometasone furoate alone in treatment of adenoid hypertrophy regarding efficacy and recurrence rate. Methods: The study included 100 children with adenoid hypertrophy, they were randomly assigned to two groups. Group I (50 patients) received combined therapy using montelukast and mometasone furoate nasal spray. Group II (50 patients) received only mometasone furoate nasal spray. Patients were treated for 3 months and observed for 3 months after stoppage of treatment. Patients were evaluated using symptoms scores, Adenoid/Nasopharyngeal ratio and endoscopic grading of adenoid hypertrophy. Results: After 3 months of treatment, group I showed significant better scores of main symptoms than group II; (P = 0.001), (P = 0.019) and (P = 0.008) for rhinorrhea, mouth breathing and snoring respectively. The mean A/N ratio was 52.8 ± 11.3 in group I better than 62.88 ± 12.10 in group II (P < 0.001). Regarding the adenoid hypertrophy grading, significant reduction in size was found in group I in 34 (68%) patients better than in group II in 18 (36%) patients (P = 0.001). After further 3 months of follow up, the mean A/N ratio was 58.46 ± 10.05 in group I better than 66.36 ± 10.46 in group II (P < 0.001). Recurrence occurred in 8 (23.5%) cases out of 34 improved cases in group I better than 10 (55.5%) cases out of 18 cases in group II (P = 0.02). Conclusion: Combining oral montelukast with intranasal mometasone in treatment of adenoid hypertrophy provided better improvements and less recurrence in comparison with single therapy using intranasal mometasone alone.