Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in the Notch3 gene on chromosome 19. The condition manifests itself clinically typically in the third to fifth decade with migraine and recurrent episodes of stroke or transient ischaemic attacks. We report the case of an 11-year-old male with CADASIL resulting in stroke with right hemiparesis and dysphasia. Acute magnetic resonance imaging suggested infarction in the left hemisphere; magnetic resonance angiography revealed calibre variation of the intracerebral arteries. The patient suffered from common migraine with five to six attacks per month for 3 years 6 months before the stroke. Attacks occurred early in the morning with severe one-sided headache, photophobia, nausea, and vomiting. Antimigraine medications had no effect. The family history revealed more cases of CADASIL, with an autosomal dominant pattern. The diagnosis of CADASIL was confirmed by the finding of the known mutation of the Notch3 gene running in the family. With treatment in a neurorehabilitation centre the patient recovered most of his functions with only discrete fine-motor and cognitive sequelae. Our case report highlights the need for paediatricians to consider CADASIL in childhood stroke as well as in migraine patients.