Although rare, insulinomas are the most common functioning islet cell tumour of the pancreas. Recognition of the key neuroglycopenic symptoms should trigger the initial investigation. Biochemical proof of endogenous hyperinsulinemic hypoglycemia establishes the diagnosis. Several options are available for imaging and localizing these tumours including ultrasonography, computed tomography, and intra-arterial calcium stimulation with venous sampling. The tumours are usually small, single, benign, well-circumscribed, and evenly distributed throughout the pancreas. This tumour may be a part of the multiple endocrine neoplasia type 1 (MEN-1) syndrome, in which case the tumours are almost always multiple. Surgical treatment is the only curative method, traditionally accomplished with enucleation or partial pancreatic resection. Patients are almost invariably cured lifelong with complete excision of a benign insulinoma. The most recent developments in this area are the recognition of noninsulinoma pancreatogenous hypoglycemia syndrome as a cause of organic hypoglycemia, and the development of laparoscopic techniques to excise these tumours.