This chapter contains detailed, up-to-date information about the nature, diagnosis, and treatment of Ehlers-Danlos syndromes (EDS) that cause strokes. The EDS are a group of connective tissue diseases classically characterized by fragile or hyperelastic skin, hyperextensible joints, vascular lesions, and easy bruising and excessive scarring after an injury. Numerous mutations of the COL3A1 gene on chromosome 2, including point mutations, exon skipping mutations, and multi-exon deletions, have been attributed to this disease. EDS patients develop arterial dissections. The cerebrovascular complications include intracranial aneurysms, arterial rupture, carotid-cavernous fistulae, and arterial dissections. The intracranial internal carotid artery is the most common site for an aneurysm, and rupture of the internal carotid artery within the cavernous sinus can create a direct carotid-cavernous fistula. The fragile arteries make angiography and surgery difficult, but some patients have had successful surgery or endovascular treatment.