Inhaled albuterol is the most frequently used bronchodilator for acute wheezing, and nebulization is the standard mode of delivery in hospital setting. However, recent guidelines consider spacer devices as an easier to use, and cost-saving alternative and recommend the high-dose metered-dose inhaler bronchodilator. OBJECTIVE To demonstrate clinical equivalence between a spacer device and a nebulizer for albuterol administration. METHODS Randomized, double-blind, parallel group equivalence trial. METHODS Pediatric emergency wards at 2 tertiary teaching hospitals. METHODS Sixty-four 12- to 60-month-old children with acute recurrent wheezing (32 per group). METHODS Albuterol was administered through the spacer device (50 microg/kg) or through the nebulizer (150 microg/kg) and repeated 3 times at 20-minute intervals. Parents completed a questionnaire. METHODS Pulmonary index, hospitalization, ease of use, acceptability, and pulse oximetry saturation. RESULTS The 90% confidence interval of the difference between treatment groups for the median absolute changes in pulmonary index values between T0 and T60 was [-1; +1] and was included in the equivalence interval [-1.5; +1.5]. Clinical improvement increased with time. Less than 10% of the children (3 in each group) required hospitalization (2 in each group attributable to treatment failure). Parents considered administration of albuterol using the spacer device easier (94%) and better accepted by their children (62%). CONCLUSIONS The efficacy of albuterol administered using the spacer device was equivalent to that of the nebulizer. Given its high tolerance, repeated 50-microg/kg doses of albuterol administered through the spacer device should be considered in hospital emergency departments as first-line therapy for wheezing.