A 50-yr-old woman had a right upper lobectomy that revealed the pathologic changes of eosinophilic pneumonia and mucoid impaction. In the mucus plug within the segmental bronchus, aspergillus was demonstrated by direct staining. A diagnosis of allergic bronchopulmonary aspergillosis was made. After a latent period of 17 yr, she presented with the clinicopathologic features of the Churg-Strauss Syndrome. The putative role of aspergillus in the etiology of this syndrome is discussed.