Computed tomography (CT) was used in 33 patients to evaluate possible extralaryngeal causes of vocal cord paralysis (22 left, 11 right). Neoplasm in the lower neck or upper mediastinum (lung, esophagus, thyroid, breast, lymphoma) was found to be the predominant cause (27/33). A negative CT examination correlated with a neuropathic (e.g., diabetes) or idiopathic etiology. CT proved useful in demonstrating or excluding abnormalities in areas that are difficult to evaluate by physical examination or conventional radiography, particularly the aortopulmonary window. The normal anatomy and pathologic masses involving the recurrent laryngeal nerve are illustrated.