Asthma and allergic rhinitis (AR) form a well-recognized comorbidity. This study aims at assessing the efficacy of nasally inhaled beclomethasone dipropionate (BDP) in their simultaneous treatment. A randomized controlled trial was conducted with 78 allergic rhinitis and asthma patients aged 5–17 years. Seventy-five individuals completed the study. During 8 weeks, 38 subjects received BDP-CFC aerosol (≥ 500 mcg/day) exclusively via nasal inhalation through a facemask attached to a plastic valved spacer. The control group (37 patients) received 200 mcg/day of aqueous intranasal beclomethasone plus oral inhalation of BDP-CFC (≥ 500 mcg/day) through a mouthpiece connected to the same spacer. Primary outcomes analyzed in order to assess the response to treatment were clinical scoring for allergic rhinitis and measurements of nasal inspiratory peak flow (NIPF). AR clinical scoring and NIPF did not differ in the two groups at admission or at nearly all follow-up visits. Nasal inhalation of beclomethasone dipropionate provides AR symptom relief while maintaining control of asthma by delivering it to the lungs. Therefore, this therapeutic strategy might be considered for patients suffering from this comorbidity, especially in low-resource countries, since it is less expensive than the conventional treatment. © 2004 Wiley-Liss, Inc.