A young Golden Retriever dog developed severe respiratory distress following an initial clinical diagnosis of infectious tracheobronchitis. Severe expiratory flow limitation, associated with exertional respiratory distress and hypoxemia was present. Thoracic images obtained with conventional radiography were characterized by hyperinflation and abnormal bronchial and alveolar patterns. Computed tomography was performed and in conjunction with pulmonary functional changes was diagnostic of small airway disease. The dog was treated with a variety of antibiotics, anti-inflammatory agents, and antitussives, but the clinical signs worsened and the puppy was euthanized. Pathologic examination confirmed severe small airway disease, with emphysema and bronchiolitis.