The authors report a study in which otoneurological tests were employed in order to determine the possibility of radio-induced alterations in the brainstem of patients with a rhinopharyngeal carcinoma, which extended to basicranial structures, who had undergone radiotherapy. The case report includes 16 patients; 10 males and 6 females, aged from 37 to 82, all with rhinopharyngeal tumors. All the subjects underwent Co 60 radiotherapy (44-68 Gy); the brainstem received from 40 to 100% of the total dose. Otoneurological evaluation prior to and following radiotherapy was performed employing pure tone audiometry, ABR, rotatory tests, saccadic eye movements, smooth pursuit. After RT treatment, ABR analysis revealed an abnormal wave I-V interpeak interval in 40% of the cases and pathologic in 37%. Smooth pursuit, saccades and sinusoidal rotation analysis showed important alterations respectively in 21%, 6% and 12% of the subjects. The most significant variations were in patients who received more than 60 Gy. The data gathered regarding abnormalities of otoneurological parameters indicate a probable close relationship between these modifications and precocious radio-induced brainstem damage.