Destruction of the organ of equilibrium by means of direct application of ultrasonic waves to the exposed bony semicircular canals was first carried out in man by Krejici, and was then perfected by Arslan. Many reports have confirmed the success of this therapy in cases of Ménière's disease which had been resistant to the more conservative types of treatment. This case report is presented to illustrate the successful application of this type of therapy to a patient having recurrent vertigo, primarily positional in type, with a chronic suppurative mastoiditis. There are no previous reports in the literature demonstrating the use of ultrasonic therapy in this type of situation, although some previously reported Ménière's disease cases may have been of this etiology. Report of Case In June, 1960, a 70-year-old white female was referred from the medical clinic because of recurrent episodes of vertigo, associated with nausea and vomiting. These