Background: Many pediatric patients present to the otolaryngologist with snoring and obstructive sleep apnea due to adenoid enlargement, which requires adenoidectomy. Due to the adenoid importance for immunity in early childhood, and the risks of anaesthesia and operative complications, an alternative medical treatment has been considered. Aim: To compare the effect of mometasone spray and montelukast, each alone or in combination on the symptoms and size of obstructive adenoid in children aged 3-13 years. Patients and Methods: A prospective randomized non-blinded study was conducted at Al-Jumhoori Teaching Hospital from August 2019 to November 2020. It included 95 patients (males 47, females 48) with nasal symptoms attributed to adenoid enlargement; they were randomly assigned to three groups; group (I) taking mometasone , group (II) taking montelukast , and group (III) taking both. Treatment continued for two months. Clinical scores were taken after two months of treatment, and then one month after cessation of treatment. Results: In group I there was improvement at three months of nasal obstruction and adenoid size. In group II there was improvement at three months of cough only. In group III there was improvement at three months of nasal obstruction, cough and adenoid size. Conclusions: There is significant improvement of adenoid size and symptom score with mometasone and montelukast, each alone or in combination. Mometasone has a better effect on adenoid size and symptoms than montelukast at two months, with less recurrence of adenoid size and symptoms one month after cessation of treatment. Combined therapy of mometasone and montelukast showed marginal improvement over mometasone alone at two months. At three months, there is no advantage of combined treatment over mometasone alone.