The topographic diagnostic significance of nystagmus was studied in 4887 patients with vertigo and/or dysequilibrium. The incidence of gaze nystagmus was 11% in the entire group. Sixty percent of patients with central pathology demonstrated gaze nystagmus. Horizontal gaze directional nystagmus indicated central disturbance and horizontal direction-fixed gaze nystagmus was also observed frequently in patients with central lesions. The incidence of positional nystagmus was 37% in the entire group. Horizontal rotatory direction-fixed positional nystagmus was demonstrated almost exclusively in patients with peripheral disorders. The incidence of direction-changing type of positional nystagmus was the same in patients with central and labyrinthine lesions. Pure rotatory positioning nystagmus was demonstrated mainly in patients with labyrinthine lesions and vertical positioning nystagmus in those with central lesions.