A 1/3 octave spectral analysis was performed on 2 sentences spoken by 5 patients with laryngeal cancer, 5 with head/neck cancer not involving the vocal cords and 12 normal subjects. Recordings were made prior to and at weekly intervals during radiotherapy as well as at periodic intervals posttreatment. Patients with laryngeal cancer exhibited lower spectral levels than normal throughout radiotherapy as well as several months posttreatment. By 1 yr after treatment, the spectral levels of these patients were in the normal range. Patients with head/neck cancer not involving the vocal cords exhibited greater than normal sound pressure levels throughout most of the spectrum. These levels remained high even at 1 mo. posttreatment. Irradiation of normal vocal cord tissue also seems to result in higher spectral levels.