We report a case of a carotid body tumor associated with a primary differentiated thyroid carcinoma. A 44-year-old woman presented with a 10-year history of an asymptomatic mass in her neck. Physical examination revealed a pulsatile submandibular mass in her right neck as well as multiple nodules in the thyroid. Magnetic resonance imaging, computed tomography and, in particular, angiography were diagnostic of the carotid body tumor. Slight changes in serum thyroglobulin levels and thyroid scintigraphy led us to suspect thyroid carcinoma. Embolization of the arteries feeding the carotid body tumor was performed, and was followed by tumor resection 24 h later. At surgery, histopathology confirmed the presence of follicular and papillary carcinomas of the thyroid, resulting in concurrent resection of the gland. There were no residual cranial nerve deficits. The patient subsequently received radiotherapy. Diagnosis and surgical management are discussed, together with pathogenetic factors.