A 20 month old castrated male American Cocker Spaniel was referred to Cornell for evaluation of a chronic, non-productive cough. Thoracic radiographs disclosed a large, cavitary mass and focal airspace pattern in the right accessory and caudal lung lobes respectively. Neoplasia and abscess were top differentials. Cytology showed a predominantly neutrophilic mixed inflammation with necrosis and hemorrhage. CT confirmed the extent of the lesion and a thoracotomy was performed, removing the right accessory and caudal lung lobes. A cyst like structure containing yellow-green purulent material was excised from the lung tissue. Aerobic, anaerobic, and fungal cultures yielded no growth, and the cough persisted despite broad spectrum antibiotic therapy. Histopathology was consistent with Canine Eosinophilic Bronchopneumopathy, and the dog's clinical condition resolved following immunosuppressive doses of prednisone.