Objective: To determine whether 2 doses of dexamethasone is as effective as 5 days of prednisolone/prednisone therapy in improving symptoms and quality of life of children with asthma exacerbations admitted to the emergency department (ED)., Study Design: We conducted a randomized, noninferiority trial including patients aged 1-14 years who presented to the ED with acute asthma to compare the efficacy of 2 doses of dexamethasone (0.6 mg/kg/dose, experimental treatment) vs a 5-day course of prednisolone/prednisone (1.5 mg/kg/d, followed by 1 mg/kg/d on days 2-5, conventional treatment). Two follow-up telephone interviews were completed at 7 and 15 days. The primary outcome measures were the percentage of patients with asthma symptoms and quality of life at day 7. Secondary outcomes were unscheduled returns, admissions, adherence, and vomiting., Results: During the study period, 710 children who met the inclusion criteria were invited to participate and 590 agreed. Primary outcome data were available in 557 patients. At day 7, experimental and conventional groups did not show differences related to persistence of symptoms (56.6%, 95% CI 50.6-62.6 vs 58.3%, 95% CI 52.3-64.2, respectively), quality of life score (80.0 vs 77.7, not significant [ns]), admission rate (23.9% vs 21.7%, ns), unscheduled ED return visits (4.6% vs 3.3%, ns), and vomiting (2.1% vs 4.4%, ns). Adherence was greater in the dexamethasone group (99.3% vs 96.0%, P < .05)., Conclusion: Two doses of dexamethasone may be an effective alternative to a 5-day course of prednisone/prednisolone for asthma exacerbations, as measured by persistence of symptoms and quality of life at day 7., Clinical Trial Registration: clinicaltrialsregister.eu: 2013-003145-42., (Copyright © 2017 Elsevier Inc. All rights reserved.)