Fifteen children with islet-cell tumor (s) of the pancreas and ulcer diathesis (Zollinger-Ellison syndrome) were collected in a tumor registry established to study pathophysiology and natural history of this syndrome. Eight children had less than total gastrectomy and six of these died. Five died from complications of recurrent ulcerations. All seven children with total gastrectomy remain alive and well. Metastatic or multiple tumors or both were present in all seven at the time of total gastrectomy. Follow-up bioassay or gastrin radioimmunoassay studies were performed in six of the seven patients. Serum gastrin levels remained elevated for periods of 5 and 11 years in two patients. Presumably gastrin-producing tumor remains in those patients. One patient with increased gastrin six years after total gastric resection now has low levels after eight years. Two other patients have progressively lower levels each year following total gastrectomy.