This study was designed to investigate the clinical effect of montelukast sodium combined with inhaled corticosteroids in the treatment of children with obstructive sleep apnea syndrome (OSAS).One hundred ninety-five children were enrolled and divided into 3 groups: groups A, B, and C; the group A (oral use of montelukast sodium), group B (nasal spray of mometasone furoate), and group C (oral use of montelukast sodium + nasal spray of mometasone furoate). Telephone questionnaire surveys were carried out. Polysomnography monitoring was performed and lateral x-ray radiographs of the cervical spine were taken before treatment and at 12 weeks after treatment. The improvement of clinical symptoms after treatment and its effective rate were analyzed. The difference in clinical characteristics between groups C1 and C2 was analyzed.In the 3 groups, clinical symptoms improved at 12 weeks after treatment compared with before (P < .05 or P < .01). Apnea-hypopnea index value decreased (P < .05) and minimal SaO2 increased (P < .05), while adenoidal/nasopharyngeal ratio was reduced (P < .05). Compared with groups A and B, group C had a shortened response duration of snoring, apnea, and restless sleep (P < .05). Differences in the response duration of buccal respiration and hyperhidrosis were not statistically significant (P > .05). The total effective rate was higher in group C than in A and B (P < .05), while the differences in all indices between groups A and B were not statistically significant (P > .05). The difference in the grade of the size of the tonsil between groups C1 and C2 was statistically significant (P < .05).The total effective rate of the combined treatment was higher than that of the single use of any of the 2 drugs, which allowed the rapid relief of symptoms. Drug treatment may have a poor curative effect in the treatment of OSAS patients with ≥ grade 3 tonsil hypertrophy.