Sudden sensorineural hearing loss has been reported to occur following anesthesia and various non-otologic surgeries, mostly after procedures involving cardiopulmonary bypass. Unilateral sensorineural hearing loss resulting from microembolism is an infrequent complication of cardiopulmonary bypass surgery that has long been acknowledged. Moreover, there are few reports on the occurrence of bilateral sensorineural hearing loss without other neurologic deficits and its etiology has also not been determined. We describe here a rare case of bilateral hearing loss without other neurologic deficits in an otherwise healthy 27-year-old woman who underwent cardiopulmonary bypass surgery for repair of severe mitral valve stenosis. The patient suffered from profound sensorineural hearing loss in both ears that was recognized immediately upon extubation, and audiometry tests confirmed the diagnosis. Without any treatment, her hearing recovered almost completely by the time of her discharge one week after surgery.