Spastic dysphonia is a severe disorder of voice characterized by strained, strangled, harsh, tremulous and tight phonation. Speech is interrupted by irregular stoppage and it requires considerable effort and is accompanied by facial grimacing. Several theories have been set forth in an attempt to explain this phenomenon. These include : a psychoneurosis, a form of a conversion reaction to emotional stress ; an organic disorder of the neuromuscular system ; a disturbance in the proprioceptive control of the vocal cord ; a combination of the above. However, none of these ideas completely explain this disorder. This disorder was first described by Traube in 1871, since then other many authors have reported this in developed countries, but it has not been reported in Korea. At Department of Otolaryngology of Yonsei University College of Medicine, 12 cases with spastic dysphonia who visited to Vocal Dynamics Laboratory from May, 1981, to September, 1984 were analysed. In the eighth patient, we did thyroplasty type III as a treatment. 1) The incidence of spastic dysphonia among 739 patients with voice disorder visited to our laboratory was approximately 0.6%(12 cases). 2) The onset of this voice disorder was from 22 years of age to 66 years with an average 44 years. The disease occurred most frequently in adult female. 3) The duration of symptom was from 5 months to 17 years. In average it was 5 and half years. 4) In psychoacoustic evluation, the voices of all of these patients were evaluation as grade II of III with characteristic strained factor. 5) In aerodynamic studies, indirect laryngoscopy and stroboscopy, we could not find any abnormality. 6) The eighth case underwent the thyroplasty type III. After surgery, improved voice were noticed with relief from the physical effort to phonate. But more long-term follow-up study is needed.