Features of chronic asthma include airway hyperresponsiveness, inflammatory infiltrates, and structural changes in the airways, termed remodeling. The contribution of eosinophils, cells associated with asthma and allergy, remains to be established. We show that in mice with a total ablation of the eosinophil lineage, increases in airway hyperresponsiveness and mucus secretion were similar to those observed in wild-type mice, but eosinophil-deficient mice were significantly protected from peribronchiolar collagen deposition and increases in airway smooth muscle. These data suggest that eosinophils contribute substantially to airway remodeling but are not obligatory for allergen-induced lung dysfunction, and support an important role for eosinophil-targeted therapies in chronic asthma.