Etiology of vocal fold paralysis is broad: e. g. iatrogenic/traumatic, associated with neoplasms or with systemic diseases. The cause of idiopathic paralysis is unknown. The main symptom of unilateral vocal fold paralysis is hoarseness because of a remaining glottic gap during phonation. Patients with bilateral vocal fold paralysis typically have no impairment of the voice but dyspnea. Examination of patients with an idopathic vocal fold paralysis is a CT of the vagal nerve and recurrent laryngeal nerve from skull base to neck and mediastinum. Serological tests are not obligatory. Differential diagnosis of vocal fold immobility is vocal fold paralysis/neurological causes and arthrogene causes such as arytenoid subluxation, interarytenoid adhesion and vocal fold fixation in laryngeal carcinomas. Voice therapy is a promising approach for patients with unilateral vocal fold paralysis, but not all patients benefit sufficiently. Temporary vocal fold augmentation by injection medialization results in satisfactory voice quality that is comparable with a thyroplasty. Patients with bilateral vocal fold immobility show typically dyspnea requiring immediate therapy such as temporary tracheotomy or reversible laterofixation of the paralyzed vocal chord. If the paralysis persists a definitive enlargement of the glottic airway by eg. arytenoidectomy needs to be performed.