We used a three-dimensional audiogram which displays duration of the disease on the X-axis, frequency on the Y-axis, and hearing level on the Z-axis, to aid observation of hearing changes during the course of various otologic diseases. An overall, quantitative view of the changes in a patient's hearing level with time was easily obtainable with this technique, as the temporal element is shown on the X-axis. The basal view position of the three-dimensional audiogram displays most of the information necessary to form a diagnosis, determine treatment, and evaluate is efficacy in various otologic diseases. The three-dimensional audiogram was found to be most useful in observing changes in hearing level in sudden deafness, with its often rapid recovery period, and Meniere's disease, with its long-term fluctuating hearing loss. In some patients, a better understanding of the hearing changes could be obtained from a view angle other than the basal view position.