Six hundred cases of carotid body tumors are reported in Literature. This tumor originates from ganglia cells which are able to produce catecholamines. The percentage of bilateral involvement is 32%. The hystological examination of specimens of this tumor reveals atypical cellular features in 30% of the cases. Clinically we divide this tumor into two classes: the first includes tumors whose growth is limited in the adventitial layer of the artery, while the second includes tumors with invasive growth in the arterial wall. In this paper a case of a large carotid body is reported. The importance of a correct pre-operative diagnosis based on supra-aortic-trunk angiography is stressed. A peri-adventitial surgical approach carried out with the aid of the operatory microscope is described. Particular emphasis is placed on intra-operative electroencephalographic monitoring which allows a safe vascular reconstructive surgery of the carotid complex when required.