OBJECTIVE: To show the value of rotating chair test (ROT) as an adjunct to the conventional electronystagmography (ENG) examination including caloric test for the diagnosis of vestibular lesions. BACKGROUND: Since caloric stimulatim is regarded as a very low frequency (0. 003Hz) test, it is desirable to test the function of horizontal semicircula canals by stimulating with faster frequencies. Baloh et al. (1984a) described that lesions ofdifferentiated by ROT. Leigh and Zee(1991) told that ROT can give more accurate and reproducible results than do caloric tests. METHOD: 30 patients who suffered from vertigo with either peripheral or central pathology were given computerized ENG and ROT. We discuss the representative examples of our initial experience with ROT. RESULTS: 1.In eight patients with known peripheral pathology, low-frequency phase deficits, asymmetry toward the lesim side and VOR suppression by gazefixation were seen during ROT. With bilateral peripheral vetibular disease, the ROT could identify remaining vestibular function at higher frequencies. 2. Seven patients with lesions of central vestibular structure showed abnormalities of saccades and pursuit during ENG and failure of VOR suppression by gaze fixation during ROT. 3. Out of 15 patients whose lesions could not be localized distinctly after caloric test, four patients were suggested to have central pathology. CONCLUSION: ROT can be a useful method to study the vestibular abnonnahties and an adjunct to the conventional ENG test.