In the literature only seven cases have been published describing a mobile carotid plaque, and lack of precise description makes it difficult to differentiate these lesions from mobile thrombotic lesions. The natural history of these lesions is not known and their treatment is controversial, although there is a tendency to choose the type of treatment to be given according to the embologenic potential of the lesion.We report two cases with mobile carotid plaques. In both cases diagnosis was made on ultrasound Doppler. The first patient had neurological symptoms and a mobile plaque associated with stenosis of over 70%. Surgical treatment was indicated. The second patient had no neurological symptoms. On ultrasound Doppler studies there was a fragment of mobile plaque in the common carotid artery, in the region of the carotid sinus with stenosis of 30 50%. Distal to this zone, in the bulb of the internal carotid artery there was stenosis of >70%. In this case medical treatment was given in view of deterioration in the patient s general state. Both patients improved.Including our second case, three patients with mobile carotid plaques (neurologically asymptomatic) have now been reported to have made good progress with medical treatment. Until there is more data regarding the natural history of these lesions, they should not be considered to be in themselves sufficient reason for carrying out carotid endarterectomy. The possibility of indicating surgical treatment depends on the degree of carotid stenosis.