Cerebral autosomal dominant arteriopathy with subcortical infarctions and leucoencephalopathy (CADASIL) is an inherited CNS disease, which is caused by mutations in the NOTCH3 gene. Selective disorders of small vessels underlie the disease pathogenesis. Clinically CADASIL is characterized by headaches, multiple stroke-like disorders (in most cases transient ischemic attacks and lacunar strokes), and different focal neurological symptoms and dementia. There are specific MRI signs of the disease: multiple lacunar infarctions located in the basal ganglia, brain steam and cerebellum, focal lesions of temporal poles, capsula externa, periventricular and subcortical areas; diffuse white matter changes and leukoaraiosis can be observed as well. The differential diagnosis of CADASIL is made with many diseases, which are manifested by multiple brain matter lesions, including demyelinating disorders. It should be taken into account that CADASIL is characterized by headaches as one of the initial symptoms, multiple lacunar and diffuse brain matter lesions based on MRI data with an absence of atherosclerosis and arterial hypertension. Family history and autosomal dominant mode of inheritance is also typical of CADASIL. Detection of the NOTCH3 gene mutation is necessary for the definite diagnosis of CADASIL.