In order to relate clinical, angiologic and brain-morphological findings, 107 patients with internal carotid artery occlusion were examined clinically and by Doppler sonography, computerized tomography and cerebral angiography. During computerized tomography, haemodynamically induced infarctions could be differentiated from those, caused by periocclusive embolism towards the major brain arteries. This differentiation was based on an integration of angiological as well as brain-morphological data and implicates some important diagnostic, therapeutic and prognostic consequences. The first group may benefit from immediate surgical restoration of carotid blood flow and have a relatively good prognosis. By contrast, subjects presenting territorial infarctions mostly experience severe and permanent neurological deficits. They should not undergo revascularization since endarterectomy increases the risk of cerebral hemorrhage but cannot cause clinical improvement. In five patients, following special angiographic techniques, the lesions of the internal carotid artery turned out to be pseudoocclusions. This condition threatens the patient considerably but is well accessible to surgical reconstruction. Thus, pseudooclusion seems to be one of the most convincing indication for emergency endarterectomy of the internal carotid artery.