A review is given on the way our knowledge of pathways of immune responses inside and in the immediate vicinity of the inner ear has gradually developed over the past two decades. Immune reactivity plays a more important role in the etiopathogenesis and natural course of various inner ear disorders than was thought originally. They comprise certain forms of fluctuating or rapidly progressive sensorineural hearing loss (SNHL) with or without endolymphatic hydrops. Patients may present themselves clinically with symptoms resembling Ménière's disease or even with sudden deafness. Immune-mediated audio-vestibular dysfunctioning is either a separate disease entity or part of a more generalized (auto-) immune process. The various attempts which have been made to develop methods or tests to confirm the diagnosis of immune-mediated SNHL are critically reviewed, including the treatment responses to immunosuppressive therapy. Various animal models are furthermore presented.