A case of ototoxic reaction to propylthiouracil occurred in a patient with thyrotoxocosis. The patient developed both symptoms of systemic lupus erythematosus and a unilateral, sensorineural hearing impairment. The hearing loss was diagnosed as cochlear, although certain retrocochlear symptoms were evident. Termination of drug therapy led to recovery from both physical symptoms and the auditory impairment. Careful management of patients receiving propylthiouracil and further research are indicated.