A basic study of electrocochleography (ECoG) was performed on guinea pigs with kanamycin (KM) intoxication, using the same apparatus and method as for humans. Histrogical observation of the hair cells was carried out under a light microscope after succinic dehydrogenase (SDH) staining and surface preparation. The relationship between the cochlear potentials (AP, CM and SP) and the degree of hair cell damages was examined. The following results were obtained: