The current strategy recommended for Zollinger-Ellison syndrome (ZES) has significantly improved the outcome of this condition. Diagnosis is based on determinations of basal and post-secretin gastric acid output and serum gastrin levels. A crucial step is differentiation of patients with sporadic ZES from those with multiple endocrine neoplasia type 1 syndrome. Only the former should undergo excision of the tumor when feasible. All available imaging techniques should be used pre- and intra-operatively to detect tumorous lesions. Exploratory laparatomy is warranted in patients who have sporadic ZES without evidence of liver metastases.