Allergic asthma afflicts 16 million adults and nine million children in the United States with an approximated annual cost to the economy of $14 billion. Current animal models of human allergic asthma do not accurately mimic natural environmental exposure, limiting our ability to clarify disease mechanisms responsible for acute and chronic pathogenesis. To this aim, we have developed an airborne delivery method for the clinically-relevant allergen Aspergillus fumigatus. Like the current liquid delivery system, the airborne method exhibits many of the hallmark signs of acute allergic asthma: methacholine-induced airway hyperresponsiveness, bronchial eosinophilia, lymphocyte infiltration into the lungs, and increased mucus secretion. In addition, a significant improvement in pulmonary dispersion of the fungus indicates that airborne delivery incorporates the contribution of the small airways in the disease model much as it would be in the clinical setting. This may be of particular benefit in studying chronic disease symptoms such as goblet cell hyperplasia and fibrosis.