We have evaluated 39 patients with ischemic strokes secondary to atherosclerotic disease of the extracranial carotid artery. Seven of them had been treated in the past with cervical radiotherapy for neoplastic diseases (radiotherapy group); the remaining 32 patients had not received radiation therapy (non-radiotherapy group). When the prevalence of risk factors was compared between the two groups, there was a significantly higher prevalence of peripheral arterial disease (p less than 0.05), hypertension (p less than 0.05) and atherogenicity index lower than 21.5% (p less than 0.05) in the non-radiotherapy group. Regarding angiographic data, the radiotherapy group showed a significantly higher occurrence of localized findings than the non-radiotherapy group (p less than 0.005). It is concluded that radiation-induced carotid disease is a clinical condition which may be individualized from the remaining patients with atherosclerotic carotid artery disease.