Ten heparinized nonhuman 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. An infarct was created. The lesions were monitored in vivo by computed tomography performed at intervals for I year. 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.