Thirty-five nasopharyngeal carcinoma patients with dizziness, post-irradiated, underwent a battery of audiological and equilibrium function tests. The results revealed that post-irradiation dizziness occurred on the average of 6 year after irradiation. Most (63%) of the patients with dizziness are due to otitis media and its sequelae. Therefore, frequent local treatment of ears, nose, and throat may be beneficial to decrease the incidence of post-irradiation dizziness.