Monogenic causes of stroke are rare but should not be missed by the neurologist. The purpose of this review is to aid the reader in the evaluation of a patient with cryptogenic stroke with or without a family history suspicious for an inherited condition. The clinical findings, diagnosis, and management of monogenic causes of stroke and stroke look-alikes are discussed, including cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy, Fabry's disease, vascular Ehlers-Danlos, Marfan syndrome, sickle cell disease, the thrombophilias, hereditary hemorrhagic telangiectasia, cerebral cavernous malformations, hereditary cerebral hemorrhage with amyloidosis, and mitochondrial encephalopathy, lactic acidosis, and strokelike episodes. A quick review of systems designed to screen for genetic stroke causes is presented. By correlating stroke subtype with phenotype, this review will familiarize the clinician with indications for focused genetic testing in appropriate patients.