OBJECTIVES: Despite evidence supporting the need for oral corticosteroid use in the management of acute pediatric asthma exacerbations, delays in administration are still common. This often leads to an increase in inpatient admissions and more time spent in the emergency department (ED). Using data from a time-series controlled trial, the objective of this study was to assess the cost-effectiveness of triage nurse-administered oral corticosteroids (NAC) in children presenting to the ED with moderate to severe asthma exacerbations prior to physician assessment. METHODS: Resource use and cost data for 644 acutely asthmatic patients enrolled in the controlled trial comparing NAC with standard care was used. Analysis assessed the per patient health care system costs for both the NAC (after) phase and the physician-ordered (before) phase over the trial’s 8-month follow-up. Uncertainty around estimates was assessed through nonparametric bootstrapping which allowed calculation of the probability that NAC was cost-effective for different threshold values. Net benefit regression was used to estimate the incremental net benefit (INB) adjusted for potential confounders for reduced time in ED. RESULTS: NAC was dominant over standard care as it was both less costly (Canadian $499.24 versus $724.90) and mean time to clinical improvement was shorter (218 minutes versus 264 minutes). The probability that NAC was cost-effective was greater than 0.98 for all threshold values of reduction in time with symptoms. Sensitivity analyses adopting various alternative assumptions found only modest differences in cost savings between the phases, but did not change the conclusions of the analysis. Results of the net benefit regression provided further evidence that NAC was cost-effective. CONCLUSIONS: Triage nurse initiation of oral corticosteroids before physician assessment is a cost-effective strategy for treating children with moderate to severe asthma exacerbations in pediatric ED.