This chapter reviews three disorders of the inner ear that can cause vertigo and hearing loss. As with most other disorders affecting the labyrinth and/or the cochlea, the diagnosis is based upon the history, clinical examination, and laboratorytests. Specific treatments exist for each disorder, and establishing an accurate diagnosis is important in determining the treatment options. The physiologically based approach to evaluation of symptoms and signs in patients with complaints related to vestibular and auditory function has led to significant advances in the diagnosis and treatment of perilymphatic fistula, superior semicircular canal dehiscence, and Ménière's disease. Although these conditions can have entirely different causes, their clinical manifestations can be similar.