Unilateral vocal cord paralysis refers to the immobility or limitation of mobility of a vocal cord due to neural injury. Neural injury is most commonly caused by surgical trauma or a malignant tumor. Hoarseness with various degrees is the main symptom. The typical finding is a vocal cord remaining in a laterally immobile position on the side of injury in mirror examination, when the patient is asked to produce a voice. Establishing the etiology of the paralysis often requires imaging studies in order to exclude a tumor. Treatment consists of voice therapy and, in severe cases, voice surgery.