Introduction. The term CADASIL (cerebral autosomal dominant arteriopathy with subcortical infartcs and leukoencephalopathy) refers to a hereditary systemic microangiopathy caused by mutations of the NOTCH3 gene located on chromosome 19. It typically presents in young people with migraine attacks and recurrent ischemic strokes, leading to a progressive subcortical cognitive decline over several years. Aim. To describe the symptoms of onset and clinical manifestations in 11 CADASIL patients diagnosed by genetic testing or skin biopsy. Patients and methods. Detailed physical and neurological examinations, vital signs, electrocardiogram, laboratory investigations (including glucose levels, lipid profile, coagulation studies and homocysteine levels, among others), brain MRI, Mini-Mental Test and Trail Making Test A & B were done. In addition, some patients with complaints related to depressive symptoms or impaired cognition received the Montgomery & Åsberg Depression Rating Scale and a battery of neuropsychological examinations (the Stroop Color and Word Test and the V-ADAS-cog that includes the Maze Test). Results and conclusions. Our patients presented with a clinical course and a radiological pattern similar to those described previously in the literature. We found a delay in the detection of this pathology and previous diagnostic errors in some patients and their relatives. Multiple sclerosis was the most frequent misdiagnosis. The course of the disease was barely modified by therapeutic interventions introduced to control the progression of the symptoms. Cognitive complaints in patients with advanced stages were common and the executive abilities were found to be impaired in many cases. © 2011 Revista de Neurología.