Twenty-six patients with clinically documented acute cerebral infarction were evaluated by computed tomography within the first 24 hr. In 21 patients, subtle mass effects and/or focal areas of decreased attenuation corresponding to areas of clinical deficit were demonstrated. Enhancement occurred in only five of 15 infarctions rescanned after contrast administration. In three of these, the region of infarction became isodense after contrast administration. In a patient with multifocal infarcts, enhancement was the only clue to infarction in one focus. The improved spatial and contrast resolution of current generation scanners appears to have significantly increased the sensitivity of computed tomography in demonstrating acute cerebral infarction and has important clinical application.