Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease caused by a mutation of the NOTCH3 gene. The clinical information of two CADASIL families was studied and mutation analysis of the NOTCH3 gene was performed by DNA direct sequencing. Published studies of Mainland Chinese CADASIL patients were reviewed and reanalyzed. The patients in the two families showed migraine with aura, stroke and cognitive decline. Cranial MRI revealed subcortical white matter infarcts and leukoencephalopathy. Two previously reported mutations of the NOTCH3 gene, c.397C>T and c.268C>T, were identified and cosegregated with the disease. The main clinical features, cranial MRI and pathological changes in Mainland Chinese CADASIL patients were similar to those in other regions. The frequency of migraine may be lower than that in Europe, but similar to that in Asia. Eight different NOTCH3 gene mutations were reported among Mainland Chinese CADASIL patients; of these, the c.322C>T mutation has not been reported in other regions. This study supports that the clinical features of Mainland Chinese CADASIL patients are similar to those seen in other regions and that exon 3 and exon 4 of the NOTCH3 gene are the mutation hotspots in Mainland Chinese CADASIL patients.