Questionnaires were sent to physicians and speech and hearing therapists who examined and treated patients with spasmodic dysphonia (SD) during a 5-year period from 1994 to 1999. Questioned were the number of SD patients seen in the past 5 and 1 years, age of onset, age of initial visit, sex, classification and treatment methods. The questionnaires were sent to 81 facilities in the nationwide university hospitals, of which 45 facilities, or 56%, responded. Questioned also were the number of new outpatients in the past year and the number of patients with laryngeal cancer, sudden deafness or Bell's palsy, The morbidities of patients with the above diseases were compared retrospectively with that of spasmodic dysphonia. The findings of investigation are as follows. 1. The number of patients scen in the past 5 years was 224. Sex was confirmed in 169 patients ; 31 males (18.3%) and 138 females (81.6%) or sex ratio 1: 4.4. The ratio of the females to males was relatively higher than that found in the literatures. 2 . Classification was confirmed in 169 patients, of whom 153 (91%) had adductor type and 16 (9.5%) abductor type. 3 . Age of onset as a whole was between 14 and 77 years old (average 36.7), that of adduction type was between 14 and 77 (average 37.2) and abduction type between 15 and 71 (average 33.1) . 4 . The estimated morbidity of SD per 100, 000 population was inferred to be 0.29 originating from laryngeal cancer, 0.77 from sudden deafness and 0.94 from Bell's palsy.