Allergic bronchopulmonary aspergillosis is an immunologic disease characterized by bronchiectasis and recurrent mucous plugging in asthmatics. The usual CT appearance is that of low attenuation branching structures corresponding to impacted dilated bronchi. We report a patient with allergic bronchopulmonary aspergillosis and mucous plugging manifested by high attenuation structures on CT. A follow-up examination demonstrated resolution of the mucous secretions and residual bronchiectasis. Possible etiologies for this CT appearance are discussed.