The author proposes the existence of a new entity, autoimmune sensorineural hearing loss, on the basis of diagnostic study and treatment experience with a series of 18 patients. In each case the clinical pattern did not fit with known entities and thus seemed to merit distinctive categorization. In the one patient in whom tissue was available, a vasculitis was evident, a feature of autoimmune disease. All patients responded to treatment for an autoimmune disease, namely, chronic cortisone and cyclophosphamide therapy. The author suggests that all otolaryngologists should be aware of the possibility of this condition, because it is one of the few forms of sensorineural deafness for which we have a treatment.