Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by recurrent thrombotic events and/or pregnancy morbidity that may be isolated (Primary APS) or associated with other diseases, mainly of autoimmune origin (Secondary APS). A variety of neurological symptoms may occur in association with the disease, including movement disorders. We report on a 79 year old woman with an unremarkable past medical history who progressively developed psychomotor agitation and insomnia through a period of four months, followed by an acute onset complex hyperkinetic syndrome with chorea, focal left foot dystonia, oral dyskinesias and severe speech impairment. Brain MRI showed multiple subcortical lesions without basal ganglia involvement, and a large cortical lesion in the left posterior temporal lobe that appeared to be ischemic. These findings along with a strongly elevated titer of anticardiolipin (aCL) and anti-beta(2) glycoprotein-I antibodies and positive Lupus Anticoagulant (LAC) suggested a diagnosis of Antiphospholipid Syndrome, confirmed 14 weeks later as a Primary syndrome. The autoimmune mechanisms possibly responsible for the patient's clinical picture are discussed. This case underlines the importance of taking into account APS as a cause of unusual movement disorders even in elderly patients without evidence of previous thrombotic events.