During the terminal incubation period of severe mumps infection, a 40-year-old patient suffered from large infarction in the right middle cerebral artery territory. The proximal right internal carotid artery (ICA) was occluded on angiography. Computed tomography of the neck detected a hemorrhage located ventromedial to the right common carotid artery. Four months later the right ICA was partly recanalized. Carotid surgery revealed an atherosclerotic plaque and a vessel wall, which was fragile and less compact than usually. A strong inflammatory reaction to mumps infection may have contributed to the pathogenesis of the cervical hemorrhage and to acute thrombosis and occlusion of the ICA.