Fifty patients, ages 54-79, with ischemic hemispheric strokes productive of hemiparesis, at a minimum, underwent standardized neurological evaluations, computed tomographic scanning and cerebral angiography (N = 38) or carotid ultrasound (N = 12) within 5 h of onset. A second scan was performed at 5-7 days. Clinical scores were not associated with a history of, or the presence of: hypertension, smoking or cardiac disease, including atrial fibrillation, nor with severe internal carotid artery stenosis or occlusion. Clinical scores were adversely affected by early scan abnormalities (especially mass effect), lesion size, intracranial arterial occlusions, elevated serum glucose levels and the subsequent development of hemorrhagic infarction. Glucose levels correlated with infarct size and the development of hemorrhagic infarction. Delayed intracranial arterial filling and collateral flow were associated with reduced infarct size but did not confer clinical protection. We believe that combining the initial glucose level and scan results has prognostic significance, and early angiography is valuable in characterizing infarct etiology and assessing clinical severity.