The abetalipoproteinemia is a recessively inherited defect in the formation of the proteins coating chylomicrons. Their absence compromises the transport of absorbed fats out of the enterocytes into the lymphatic system and the general circulation. Clinical features include steatorrhea, retarded growth, acanthocytosis of erythrocytes, retinitis pigmentosa and a chronic progressive neurological disorder with ataxia. We describe here the case of a 3 year old girl.