The head shaking test (HST) is an important test in neuro-otological diagnosis. In our study of 277 patients complaining of dizziness we verified this importance. The results thus obtained were compared with the results recorded in 73 normal subjects. Head shaking nystagmus was observed in 73 patients. Of these 73 cases, 42 involved central diseases and 31 cases involved peripheral diseases. Head shaking nystagmus was observed in 7 subjects of the control group. A highly significant correlation was noted between head shaking nystagmus and positional nystagmus, between head shaking nystagmus and the caloric test and between head shaking nystagmus and all the other spontaneous types of nystagmus that were investigated (eyes open in light/gaze straight ahead; eyes open behind Frenzes glasses; eyes closed; eyes open in darkness). No correlation was found between head shaking nystagmus and cervical nystagmus and positioning nystagmus. The sensitivity of head shaking nystagmus, in comparison with other types of spontaneous nystagmus, was found to be slightly higher in cases with peripheral lesions than in those with central lesions. These data confirm the diagnostic importance of this simple test. It is also important to keep in mind that the HST has no importance for topodiagnostic purposes.