Neurodevelopmental, neurological and neurophysiological aspects of the Norrbottnian type of Gaucher disease (type III) were studied in 22 patients. The findings were related to clinical stages and to whether or not the patients had been splenectomized. Neurological abnormalities were mainly found in splenectomized patients who had passed the first decade of life. The EEG findings were not diagnostic for the disease, but changes were more common in the advanced stages and among splenectomized patients. The patterns of development of neurological and neurophysiological features indicate that CNS deposition of glucosylceramide increases after splenectomy, and favor a restrictive attitude towards surgery.