Symptoms most characteristically diagnostic of insulinoma are those of neuroglycopenia. The combination of hypoglycemia and endogenous hyperinsulinemia are pathognomonic of insulinoma. Several localization techniques are available, the choice of which best depends on the best expertise at individual institutions. Intraoperative ultrasonography is helpful in localization and defining related anatomy. Enucleation of these intrapancreatic tumors is preferred, but for body and tail lesions, distal pancreatic resection may be required. Because at least 90% are benign, long-term cure with complete resolution of preoperative symptoms is expected.