In 20 patients with Gaucher disease type III (Norrbottnian variant), long-term intellectual prognoses were analyzed on the basis of psychometric tests which were performed on an average of five tests per patient. Intellectual delay was not found to be characteristic of the early stages of the disease. Slow regression occurred through childhood and adolescence. Patients splenectomized at an early stage averaged lower IQ scores in the long-term than those in whom the spleen had been spared as long as possible. These data added to other evidence of increased neurologic and other organ impairment after splenectomy, support the view that the spleen should not be removed in other than emergent situations.