The first goal of therapy is the control of gastric acid hypersecretion using PPIs or high-dose H2R antagonists. The diagnosis of Multiple Endocrine Neoplasia (MEN I) should be established early in the disease. Localization of gastrinoma tumor should be performed using a combination of endoscopic ultrasonography (EUS), somatostatin receptor scintigraphy (SRS), and computerized tomography (CT), or Magnetic Resonance Imaging (MRI). Surgical resection in sporadic ZES should be performed to attempt cure of tumor. Surgery, hormonal, chemotherapy, embolization therapy or therapeutic OctreoScan should be considered in patients with metastatic tumor.