Diseases of the respiratory tract in reptiles and amphibians can be a major cause of morbidity and mortality in captive and free-ranging animals. This lecture will review the pathology of the most common diseases of the nasal cavity, trachea, and lungs of both reptiles and amphibians, with emphasis on differential etiologies and appropriate confirmatory diagnostic testing for exotic/zoo clinicians and technicians. [Submission of this abstract was requested by Drs. Wyneken and Heatley to accompany their master classes on the anatomy and clinical features of the reptile and amphibian respiratory tract.]