In 20 normal-hearing subjects, hypoacusics and anacusics ranging from 4 to 44 years of age, we have developed a study related to the analysis of brain evoked potential: B E R, E R P 40 Hz, cochlear microphonic responses and P 300 stimulating sound in the ear, and vibration to the teeth. With vibratory stimuli to the teeth, the brainstem potential didn't appear in anacusics; however, it appeared in subjects with perception deafness and transmission deafness. The potential type E R P 40 Hz (Galambos et al, 1981) appeared in hypoacusics, but not in anacusics; however, the subjective sensation of the vibration remained with them in absence of all the auditory registrable responses; nevertheless, we were able to record the P 300. We recorded perfectly cochlear responses in anacusics using vibratory stimuli of 500 Hz and higher applied to their teeth, even though they didn't have any other type of normal auditory response. The potential P 300 was obtained in normal hearing, hypocusics and anacusics, with the proper latencies according to their ages.