We report the first patient from Sri Lanka (the third patient from the Indian subcontinent) with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The patient experienced a young onset familial stroke with an 856T>G missense mutation in exon 5 of the NOTCH3 gene resulting in a C260G mutation in the sixth epidermal growth factor-like repeat. We believe this is the first reported Sri Lankan patient. CADASIL is probably underdiagnosed in the region.