Only a few case reports have been published about hearing impairment following lumbar puncture, and not all were thoroughly documented by audiograms. We present nine cases of hearing loss following myelography, lumbar puncture, and spinal anesthesia. We speculate that this rare complication arises only in persons with a wholly or partially patent cochlear aqueduct, and occurs via the release of perilymphatic fluid in the cerebrospinal space. Hearing loss was seen in eight of the nine patients in the lower frequencies, and in six of the nine patients on both sides. Recovery to normal hearing was noticed in six of the nine patients. Transient hearing loss may occur more often than it is generally assumed, and the symptom can remain unnoticed. Since not all of these hearing losses proved to be fully reversible, we suggest informing patients about this complication for medicolegal reasons.