The aim of this study was to assess whether carotid plaque morphology is an independent predictive factor of stroke and, innovatively, of acute coronary syndrome (ACS). We analyzed morphological aspects of carotid atherosclerotic plaque associated with an increased risk of ACS and stroke. We examined 72 carotid endarterectomy (CEA) specimens obtained between January 2005 and February 2009. All patients underwent follow-up for 12 months after the revascularization treatment to assess the occurrence of ACS and stroke. Data obtained showed that in patients with a previous ACS and in those who had developed an ACS during follow-up after CEA, the degree of carotid plaque calcification was more severe than in patients who did not develop an ACS, either before CEA or during follow-up. However, plaques of patients with ACS were mostly devoid of a significant inflammatory component, whereas a rich infiltrate, mainly consisting of monocytes-macrophages and lymphocytes, was present in plaques of subjects who did not develop an ACS. This element was particularly important since strokes occurred only in the latter group of patients (62% versus 0%). Therefore, we deduced that inflammation, from the histological point of view, is more correlated with cerebral circulation disorders than with coronary disease. In conclusion, while the finding of a soft plaque with a large necrotic core and a marked inflammatory component, often characterized by acute complications, may be predictive of an increased risk of cerebro-vascular events, a heavily calcified plaque may be indicative of a high risk of coronary events.