Pancreatic endocrine tumors are rare, yet can cause significant morbidity due to excessive secretion of hormones. Octreotide is effective in reducing the plasma concentrations of many of these hormones. The availability of potent H2-receptor antagonists and omeprazole has altered the emphasis in patients with Zollinger-Ellison syndrome away from total gastrectomy and towards resection of the gastrinoma for potential cure. Fifty percent of insulinomas and gastrinomas are not evident on preoperative imaging studies, despite their sophistication. Calcium angiography, endoscopic ultrasonography, isotope-labeled octreotide scanning, and injection of methylene blue during secretin angiography are recent imaging modalities that have shown promise in the localization of these tumors. Intraoperative ultrasound has emerged as the best method for operative detection of insulinomas. Duodenotomy and intraoperative endoscopic transillumination are especially important in the surgical management of Zollinger-Ellison syndrome because 30% to 40% of gastrinomas are located in the duodenum. The management of patients with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome continues to be controversial. Some advocate an aggressive surgical approach, whereas others have had little success in rendering patients eugastrinemic.