Among non-chromaffin paragangliomas, the so-called aorticopulmonary or branchiomeric mediastinal chemodectomas are very rare tumors. A case is reported, and 57 similar cases described in the literature are reviewed. As recommended by Olson, a separate group was instituted of 21 cases of the so-called posterior mediastinal or aorticosympathetic group of the costovertebral groove. In principle, aorticopulmonary chemodectomas are non-functional, and in 9 out of 10 cases follow a slow and benign course extending over many, or even tens of years. In contrast to carotid and jugular paragangliomas they are rarely multifocal: when this is the case it is difficult to confirm the presence of metastases, this being however the most reliable criterion of their malignancy. The fortuitous discovery on a radiography of a tumor of the anterior and middle compartments of the upper mediastinum should invoke the presence of an aorticopulmonary chemodectoma, and lead to arteriography of the aortic arch region. Diagnosis is made essentially by pathological examination. Treatment is exclusively by surgical excision, and this was complete in nearly half of the cases treated. Prognosis is not hopeless after partial removal, however, and a relatively comfortable survival can be obtained extending over many years.