A seven-year history of repeated right-sided weakness in a 10-year-old child was diagnosed by carotid arteriograms as extracranial stenosis of the left internal carotid artery. Arteriograms also demonstrated multiple congenital abnormalities of the collateral circulation at the circle of Willis. The attacks were triggered by anxiety states which developed from parental disciplinary confrontation or athletic competition. There have been no strokes since the carotid stenosis was corrected surgically five years ago. The stenosis was secondary to scarring, probably of both traumatic and inflammatory origin.