Between 1974 and 1988, 10 Mayo Clinic patients had unresectable, locally recurrent, or partially resected chemodectomas. Of these 10 tumors, 9 were confirmed pathologically, and 1 was diagnosed clinically. The chemodectoma was located in the jugular bulb in five patients, the middle ear in three, and the carotid body in two. The following symptoms were noted: tinnitus (in eight patients), loss of hearing (in six), hoarseness (in six), dysphagia (in four), pain (in three), and alteration of mental status (in one). Many patients had more than one symptom. Treatment was delivered with megavoltage photons and electrons; total doses ranged from 16.2 to 52 Gy (median, 46 Gy), and the daily doses ranged from 1.6 to 2.4 Gy. Follow-up among the nine survivors ranged from 3 1/2 to 16 years (median, 7 1/2 years). In one patient, the response could not be assessed because the patient died of renal failure 4 months after treatment. All nine assessable patients had decreased symptoms and objective control of the tumor (no evidence of progression of disease). Of the nine assessable patients, four had complete responses, one had a partial response, and four had stable disease. No patient experienced progression of disease after radiotherapy. We conclude that radiotherapy for chemodectomas yields successful results--namely, decreased symptoms and objective control of the tumor.