There are four types of cerebral vascular malformations: arteriovenous malformations (AVMs), cavernous malformations (CMs), capillary telangiectasies, and venous malformations. This chapter presents a review of the pertinent literature on CMs regarding epidemiology, genetics, pathology, clinical findings, and therapeutic management with special emphasis placed upon the natural bleeding risk of these malformations. The most sensitive imaging study to detect CMs is magnetic resonance imaging (MRI). Predictive factors for intracranial hemorrhage in patients harboring CMs is a critical issue because the optimal therapeutic management of such lesions is tailored according to the bleeding risk. The main goal of radiosurgical treatment should be a significant reduction in bleeding risk, especially after a latency period of 2 years. By genetic linkage analyses, three cerebral CM loci have been assigned to chromosome 7p, 7q, and 3q. They account for all familial forms of CM, thus constituting a formidable Mendelian model of stroke.