We correlated the clinical and pathologic findings in 77 consecutive carotid plaques removed at endarterectomy to determine the clinical role of intraplaque hemorrhage. Intraplaque hemorrhages of various severity were seen in 86% of plaques. They were, for the most part, deeply located (63%) and infrequently connected with the lumen. They related closely to the severity of carotid stenosis, but bore no relationship to the timing of symptoms. Luminal thrombus was infrequently seen, and was always microscopic. Hemorrhage into carotid plaque appears to represent an index of the severity of the stenosis and plaque instability rather than to play a direct role in the pathogenesis of transient ischemic attacks or stroke.