In order to clarify the diagnostic significance of eye tracking tests (ETT), optokinetic nystagmus tests (OKN), and visual suppression test (VST) on routine ENG tests, we investigated the findings of ETT, OKN, and VST in 1, 225 patients who complained of vertigo and dizziness, and in 440 of the patients, we compared these findings with MRI abnormalities.Abnormal results of ETT, OKN, and VST were seen in 433 patients (35.1%), 399 patients (32.6%), and 128 patients (10.5%), respectively. All tests showed impairment in 66 patients (5.4%). Both ETT and OKN abnormalities with normal VST were observed in 173 patients (14.1%), while 356 patients (29.1%) had abnormal findings for ETT, OKN, or VST. In the patients who had severely impaired ETT, OKN, or VST, there was a significantly higher proportion of infratentorial lesions on MRI than in the other patients. In the patients with abnormalities on both ETT and OKN, infratentorial le-sions were more frequently found by MRI, and the patients who had abnormalities on all tests had the highest incidence (61.7%) of infratentorial lesions on MRI.We conclude that the evaluation of ETT, OKN, and VST abnormalities should be quite useful in the diagnosis of infratentorial lesions.