Chronic bronchitis is a syndrome defined by cough on most days for at least 2 months for which no specific cause can be identified. Older small breed dogs are most commonly affected, but bronchitis can also be documented in midsized and larger breed dogs. Diagnostic testing includes physical examination, laboratory testing, radiography, and airway evaluation via bronchoscopy, cytology, and culture. Treatment is directed at reducing exposure to irritants, reducing airway inflammation, and controlling cough.