Autoantibodies in the serum of patients with inner ear disorders have been detected using the immunofluorescence technique. In the present study the results of the use of frozen sections of non-decalcified guinea pig cochlea in the indirect immunofluorescence test are described. Human sera with positive anti-mitochondrial (AMA), anti-nuclear (ANA^S) and anti-nucleolar (ANA^N) antibodies were utilized, as well as a negative serum control and sera from three patients suffering from chronic progressive sensorineural hearing loss. The positive reactions obtained were clear and specific. Autofluorescence was minimal and non-specific reactions were negligible. The fine structure of the inner ear tissue and the cellular antigenicity present were well preserved.