The pathology resulting in defective hearing is restricted to the 8th nerve or the cochlear contents. Examination for hearing is not reliable in the early days after injury because of the disturbed condition of the sensorium. Repeated examinations are necessary in each individual case for medical or legal purposes for the detection of malingering. A case history should be elicited. 211 cases of proved skull fracture were studied and 49 cases of fracture involving the base of the skull. There was perceptive deafness in 45 cases. In cases of unilateral, longitudinal fracture, the function of hearing is more damaged as age increases. The perceptive type of deafness is most common. The ear on the side of the fracture sometimes shows a greater hearing loss than its fellow; but in a large number of cases, the loss is the same in both ears. In bilateral longitudinal fracture, 65% of the cases showed perceptive hearing loss. In labyrinthine fracture, total deafness occurred in all cases on the affected side. On the opposite side, most had some loss; and one case had a complete loss. Individuals may regain a great deal of hearing even after a month has gone by after the accident. If deterioration of hearing has not occurred in the first 6 months, the condition will probably remain stationary. Some remarks are made relative to the methods recommended by the American Medical Association for evaluating hearing loss. These probably will not be useful in evaluating the amount of loss suffered by men in the armed forces because of the method in which hearing is tested upon induction.