Head-shaking nystagmus(HSN), which is provoked by rapid and passive side-to-side movement of the head(head-shaking test, HST), is always pathological as long as it is observed under Frenzel's glasses in dark room. Many investigators assume that it is identical to latent spontaneous vestibular nystagmus and is most suitable test for screening purposes in clinical vestibular examination because of its simplicity in maneuver and capability in provoking nystagmus. Authors studied HSN in 204 patients who visited to Department of Otolaryngology, Pusan Paik Hospital, Inje University with the complaints of vertigo/dizziness from January 1989 to June 1990 to study about the diagnostic value of HSN with comparison to normal 22 young subjects. The method of HST are performed as 30 cycles of head-shaking horizontally with the excursion of about 90 degrees within 15 seconds, and the results obtained were as follows; 1) The objects observed in this study were 204 persons, 91 males 113 females with ago distribution as 31.9% in fourth decade of highest incidence, and about 15% in third, fifth decade and above. 2) The patients were 115 labyrinthine disorders(56.4%), 21 vestibular nerve disorders(10.3%), 43 cardiovascular disorders(21.1%), 12 miscellaneous(5.9%), and 13 unknowns(6.4%). 3) There was no HSN except questionable 2-3 beats in 3 subjects among the 22 normal young subjects, 15 male and 7 female aged from 23-25 years old. 4) Positive ratio of some vestibular function tests were 12.0% in spontaneous nystagmus, 31.0% in gaze nystagmus, 23.2% in positional nystagmus, 29.0% in positioning nystagmus and 68.9% in HSN which was the highest incidence among that of various nystagmus. 5) Positive ratio of HSN in each disorder group were 78.6% in labyrinthine disorders, 89.5% in vestibular nerve disorder, 50.0% in cardiovascular disorders and 33.3% in miscellaneous group, showing very high positive ratio of HSN in the groups of labyrinthine and vestibular nerve disorders. There were high positive ratio more than 70% in Meniere's disease, delayed endolymphatic hydrops, sudden deafness with vertigo, labyrinthine concussion, circumscribed labyrinthitis, vestibular neuronitis and cerebellopontine angle tumor. 6) Monophasic HSN was appeared in 54.2% and biphasic was appeared in 45.8%. Of the monophasic HSN type I-A was appeared in 28.8%, type I-B was in 9.5%, type II-B was in 7.5%, From the all types of HSN biphasic type A was of highest incidence. Types correspond with the side of normal/lesion as monophasic type I-A, II-B and biphasic type A was appeared in 83.0%. First phase inhibited type and triphasic HSN were not found. 7) The higher degree of CP of caloric response was, the more beats of nystagmus of monophasic and second phase of biphasic HSN appeared with stastically significance, but there was no correlation between the degree of CP and the number of beats of first phase of biphasic HSN. 8) HSN were horizontal in 83.2% and horizonto-rotatory in 16.8%. Pure rotatory and vertical HSN were not found. 9) Direction of HSN was same as spontaneous/gaze nystagmus in 67.9% and opposite in 26.8%. 10) Of the 22 cases of biphasic HSN on first visit, who were able to follow up more than 3 months, the original biphasic HSN had changed to 1st phase of biphasic HSN in 59.1%, to 2nd phase of biphasic HSN in 13.6%, lost in 9.1% and not changed in 18.2%. From the above results, authors concluded that the HST is high positive response, effective method to determine the side of lesion and helpful to consider the progress of peripheral vestibular disorders.