We present the findings in a young woman diagnosed as having pulmonary infiltration with eosinophilia and asthma who was treated with beclomethasone dipropionate. Although the aerosol corticosteroid controlled bronchospasm, it did not prevent recurrent pulmonary infiltration with eosinophilia when the patient was not receiving oral therapy with corticosteroids. It is postulated that when administered in the usual dosage, an adequate amount of beclomethasone dipropionate does not reach the alveoli or interstitium to prevent or resolve the process of pulmonary infiltration with eosinophilia. This case suggests that patients with pulmonary infiltration and eosinophilia who are treated with inhaled corticosteroids for asthma must be closely observed physiologically or roentgenographically for pulmonary infiltration. These patients may need to be protected from recurrent pulmonary infiltration by the concurrent oral use of corticosteroids.