Alien hand syndrome is defined by uncontrolable actions of the arm and hand that seem to have a purpose. It is usually associated with acute focal lesions after a stroke or surgery of the corpus callosum. It has been described in chronic dementiating diseases such as cortico-basal degeneration, Alzheimer's disease, orthochromatic leukodystrophy and Marchiafava-Bignami disease. We now report a patient with Creutzfeldt-Jakob disease and alien hand syndrome, which appeared after the cognitive alterations and had characteristics of the frontal type of alien hand affecting the dominant upper limb. In the three cases described previously in the literature the alien hand affected the non-dominant hand and the abnormal movement appeared before dementia was clinically obvious. The non specific nature and poorly localising sign of alien hand is remarked. Alien hand should be added the list of features of Creutzfeldt-Jakob disease.