Objectives: To define clinical and laboratory characteristics of bilateral vestibulopathy (BV) and to propose diagnostic criteria of this disorder based on clinical and laboratory findings.Study Design: Retrospective case series review.Materials and Methods: We recruited 108 patients with a clinical suspicion of BV based on presenting symptoms (unsteadiness or oscillopsia during locomotion) and bedside (dynamic visual acuity or head impulse tests) and laboratory (bithermal caloric or rotatory chair tests) findings after excluding the patients with other disorders that may explain the symptoms.Definite diagnosis of BV was made when the patients showed abnormal findings on both bedside and laboratory tests in addition to the symptoms,whereas probable diagnosis was obtained when either the bedside or laboratory findings were abnormal along with the symptoms.Results:All patients had unsteadiness,and 36 (33%) reported oscillopsia.Diminished vestibulo-ocular responses to head impulse in both horizontal directions were present in 45 of the 100 patients evaluated.Dynamic visual acuity was impaired in 65 (95%) of the 68 patients who underwent testing.Fifty-one (57%) patients showed bilateral hyporesponsiveness during bi-thermal caloric tests.Forty-eight (53%) patients had reduced gain of the vestibulo-ocular reflex during rotatory chair test.By adopting our diagnostic criteria,93 patients (86%) were diagnosed as having BV,definite in 49 (45%),and probable in 44 (41%).Conclusion: The proposed diagnostic criteria encompass the symptoms and findings of both bedside and laboratory evaluations and may provide a valuable tool for investigating BV.