Ten haparinized primates (rhesus monkeys and Papio maryumaya baboons) were subjected to temporary occlusion of an insular branch of the middle cerebral artery with a balloon catheter creating an infarct. The lesions were monitored in vivo by computer tomography performed at intervals for 1 yr. Animals were sacrificed and the lesions examined histologically. The technique obviates the disadvantages of surgical reaction, intravascular thrombosis and gross cerebral edema observed in prior animal stroke models.