In 18 chemodectomas of the neck (6 carotid body tumours, 1 vagal body tumour and 11 tympanojugular tumours) the arterial supply and circulatory characteristics were evaluated at angiography. The arterial supply of the carotid body tumours was derived from all adjacent vessels including direct carotid body branches of the proximal external carotid artery. The arterial supply in tympanojugular tumours constantly came from both the ascending pharyngeal and retroauricular arteries and often also from the anterior tympanic artery. Other branches contributed less constantly and only to a minor degree, except for the vertebral artery in cases with tumour extension intracranially. The circulatory characteristics were constant in the series: a short arterial phase was rapidly followed by a phase of relatively long duration with marked, somewhat granular accumulation of contrast medium and also by an early filling of draining veins. The planning of the angiographic procedure in cases of chemodectoma is discussed.