A 73-year-old woman without liver cirrhosis developed choreoathetoid movements of the limbs due to portal-systemic encephalopathy. A prominent spleno-renal shunt was demonstrated by non-invasive methods (abdominal computed tomography and sonography) as well as arterial portography. The choreoathetoid movements were improved by a protein-restricted diet and administration of lactulose. A portal systemic shunt should be considered when investigating choreoathetosis, even in patients without liver cirrhosis.