CADASIL, Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, is an inherited small vessels disease that characterized by central nervous system dysfunctions caused by mutations in the Notch-3 gene. Clinical manifestations accrue due to brain’s vasculopathy, neurodegeneration, and immune system reaction. We describe here an effective method for treatment of CADASIL by using mesenchymal stem cell therapy. A CADASIL case, 36 years old man, neuroimaging and genetic analysis for Notch-3 confirmed the diagnosis, is reported. In the present case, two stem cell injections have been performed at intervals of three weeks. The patient had no significant complications in the post-transplant period. No immediate or delayed side effects following MSC infusion were observed. He developed neither malignancy nor unwanted cells or any infectious complications 18 months after the transplantation, we performed a Cerebral MRI showed stable cerebral lesions and his gate and balance improved. Anti-HLA Antibody measurement confirmed that the patient’s immune system was not stimulated by injected cells.With regard to his neurological symptoms, Scale for the assessment and rating of ataxia (SARA), The Multiple Sclerosis Functional Composite measure (MSFC), Quality of Life Assessment (QOL), and Cognitive Functioning Status (ACE-R), the patient did not has further deterioration of his previous clinical status in the follow up period of 18 months. Further studies need to be performed to show the generalizability of the results.