Ten consecutive patients with a progressive pan-autonomic failure of the Shy-Drager syndrome were investigated. Movement disorders of the vocal cords were examined with a fiber-optic laryngoscope as well as a video-recorder. Moderate to severe vocal cord paralysis was present in five of ten patients. The vocal cords were almost immobile during inspiration, while there was no limitation of the adduction during phonation. In two cases, grade of vocal cord paralysis was asymmetric. One patient developed peculiar twisting-like dystonic movements of the vocal cord. Polygraphic studies revealed that SaO2 was lowered in spite of tachypnea during sleep. In two cases, the expiratory flow volume curve in effort-dependent portion near TLC showed a plateau and the inspiratory part of the curve also showed a plateau indicating constant flow. These functional disorders suggest an upper airway obstruction probably due to the vocal cord dysfunction. There was no vocal cord paralysis in two patients who had neither snore nor stridor. Development of a severe vocal cord dysfunction usually manifested itself clinically as stridor, snore or respiratory failure requiring tracheostomy. There was little information on the pathology of the vagal nerves and nuclei supplying motor control to the laryngeal muscles. The mechanism of the selective involvement of abductor muscle (posterior muscle) of the vocal cord (Gerhardt syndrome) remains unsolved. Vocal cord paralysis should be looked for since it can result in respiratory failure leading to death.