The glucagonoma syndrome is caused by a glucagon-secreting pancreatic neuroendocrine neoplasm (glucagonoma). The syndrome includes: a characteristic rash termed necrolytic migratory erythema, painful glossitis, cheilitis & stomatitis, weight loss, anemia, new-onset or worsening diabetes mellitus, hypoaminoacidemia, low zinc levels, deep vein thrombosis, and depression. At diagnosis, a glucagonoma is usually 4-5 cm in size and accompanied by distant metastases, particularly to the liver. The incidence of glucagonoma syndrome is 1-2% of all pancreatic neuroendocrine tumors. Approximately 10% of glucagonomas are associated with multiple endocrine neoplasia type-1 (MEN-1). Glucagonomas highly express somatostatin receptor subtypes (97%) and therefore somatostatin receptor positron emission tomography (PET) with DOTA-labelled somatostatin analogs (DOTATATE, DOTANOC, and DOTATOC) can be used in the localization of glucagonomas. The somatostatin receptor subtypes can also be utilized for the treatment of metastatic glucagonomas with somatostatin analogs or 177Lu-DOTATATE. Other treatment options include sunitinib, everolimus, systemic cytotoxic chemotherapy, and liver-directed therapies. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.