Seckel syndrome is an autosomal recessive disorder characterized by intrauterine and postnatal growth delay, microcephaly with mental retardation, and facial dysmorphisms including micrognathia, a recessed forehead, and a large beaked nose. Occurring in 1 in 10,000 children without sex preference, it is the most common primordial microcephalic osteodysplastic dwarfism and has been associated with a variety of congenital brain malformations and intracranial aneurysms. Moyamoya syndrome is an idiopathic, chronic, progressive cerebrovascular disorder marked by stenosis of the intracranial internal carotid arteries and concurrent development of hypertrophied collateral vessels. These tortuous arterial collaterals appear radiographically as "puffs of smoke," giving the syndrome its name. In this report, the authors describe the case of a 16-year-old girl with coincident Seckel and moyamoya syndromes. To their knowledge, this is the first reported case of such an association being treated with surgical revascularization. The patient presented with persistent headaches and a 2-year history of progressive hand, arm, and face numbness. Imaging studies revealed multiple completed cerebral infarcts, global ischemic changes, and vascular anatomy consistent with moyamoya syndrome. Bilateral pial synangioses successfully revascularized each hemisphere with resolution of the patient's symptoms. The patient died 1 year later of complications related to treatment of a rapidly progressing intracranial aneurysm. This report documents the first case associating moyamoya and Seckel syndromes. In addition, the report reveals the rapid development of an intracranial aneurysm in a patient with this syndrome. When coupled with previous reports of other types of cerebrovascular disease in patients with Seckel syndrome or other primordial dwarfisms, the authors' findings are important because they suggest that physicians treating patients with dwarfism should consider the diagnosis of moyamoya syndrome when symptoms suggestive of cerebral ischemia are present. Prompt diagnosis and treatment of moyamoya syndrome, including the use of proven surgical revascularization procedures such as pial synangiosis, may significantly improve the long-term outcomes of these patients.