A 10-year-old girl with acute-onset hemichorea had multiple areas of abnormal signal seen on magnetic resonance imaging of the brain, associated with middle and anterior cerebral artery vasculitis seen on cerebral angiography. Her serology and clinical course were supportive of the diagnosis of Sydenham's chorea. Other causes of cerebral vasculitis were excluded. Follow-up studies revealed resolution of changes seen on magnetic resonance imaging and partial resolution of angiographic abnormalities. This is the first report of abnormal cerebral angiography in Sydenham's chorea.