['We investigated whether the presence of nonrelevant cerebral atherosclerosis (NRCA) had prognostic value in patients with acute stroke.', 'We compared prognosis in 780 consecutive patients with first-ever acute cerebral infarction who underwent cerebral angiography and diffusion-weighted MRI.', 'NRCA was present in 267 patients (34.2%). Multivariate analysis demonstrated that the presence of NRCA was independently associated with less improvement in National Institute of Health Stroke Scale score during the first 7 days (P=0.004), and a poor functional outcome (modified Rankin Scale score >2) after 3 months (odds ratio, 2.51; 95% confidence interval, 1.55-4.07). An increase in burden count of NRCA was also associated with poor outcomes.'] Is nonrelevant cerebral atherosclerosis a strong prognostic factor in acute cerebral infarction?