OBJECTIVE To compare the efficacy and safety of continuous nebulized (CN) albuterol therapy with those of intermittent nebulized (IN) albuterol therapy in the ED treatment of children with moderate to severe asthma exacerbations. METHODS A prospective, randomized, single-blind study was conducted at a children's hospital ED. Patients aged 2 to 18 years with a moderate to severe asthma exacerbation (asthma score > or = 8) were enrolled. Patients were randomized to receive either IN albuterol (0.15 mg/kg/dose every 30 min) or CN albuterol (0.3 mg/kg/hr) for a maximum of 2 hours. All patients received prednisone at entry. All released patients were evaluated by telephone, 48 hours after the ED visit. Estimates of respiratory therapist (RT) time commitments for the 2 delivery systems were calculated. RESULTS There were 35 patients assigned to IN therapy and 35 to CN therapy. Nine of the 35 patients (26%) in the IN group and 8 of the 35 patients (22%) in the CN group were hospitalized (p = NS). Although the durations of ED therapy were comparable in the 2 groups, the time spent by the RTs in delivering asthma therapy was significantly less for the CN group than it was for the IN group (30.3 min vs 51.9 min per patient; p < 0.001). There was no major adverse effect in either study group. CONCLUSIONS There was no difference in efficacy or safety between CN therapy and IN therapy in the ED management of moderate to severe asthma exacerbations in children. Moreover, CN therapy provided a significant time savings in the delivery of asthma therapy to patients in a busy ED.