Patients with sickle cell disease appear to have a high incidence of cerebral aneurysm. These aneurysms are not associated with the usual risk factors of hypertension, renal disease, or connective tissue disease. We present two recent cases of patients with sickle cell disease and multiple cerebral aneurysms, review the literature on the association between sickle cell disease and cerebral aneurysms, and discuss a mechanism by which sickle cell disease may lead to the formation of cerebral aneurysms.