The audiometric findings on 23 patients with diquited hypothyroidism for a minimum of 4 months to a maximum of 20 years are presented. Audiometric tests, including acustic impedance measurements (tympanometry, stapedius reflex) were performed on all patients before and after an adequate substitution therapy. In 12 patients there was a definite impairment of hearing before the substitution therapy. Eight of them have shown a mild to moderate sensory-neural deafness. Four showed a mixed deafness, in three of which a negative pressure of 300 mm H2O was measured in the middle ear, the fourth one had a seromucotympanon. In three patients with pure sensory-neural deafness the stapedius reflex was elicitated only 30 dB over the pure tone threshold in speech frequencies. The audiometric measurements after an adequate substitution therapy of minimum 4 months has shown a definite improvement of hearing loss.