A case of transient, severe sensorineural hearing loss with iopamidol following angiography is reported. The 26-year-old woman had previously been diagnosed with Arnold-Chiari malformation, and underwent vertebral angiography by a retrograde transfemoral catheterization. Immediately following the second injection of iopamidol she did not react on the nurse's call. An ABR revealed no response in either ear even when the click intensity was 105 dB. The patient was immediately treated with steroid and OHP. Fortunately, 24 h after the angiography she was able to communicate at a normal conversation level. Transient severe sensorineural hearing loss is thought to result from bilateral anoxia of the cochlea due to hypoplasia of the basilo-vertebral artery systems. Cochlea anoxia lasts 10-20 min after which the hearing loss is recovered.