We have reviewed data pertinent to three tumor syndromes that derive from overproduction of three GEP peptide hormones. The clinical syndrome of somatostatin excess remains well defined with diabetes, diarrhea, steatorrhea being predominant features. With the availability of assays and increasing awareness, more cases are being diagnosed in the intestine and these differ somewhat in their presentation with cholecystitis, GI bleeding, or a mass as the cardinal features. An unusual association with MEN II pheochromacytoma and neurofibromatosis is emerging. PPomas remain enigmatic. Although diarrhea is a feature, these tumors are usually silent and present with hypatomegally, abdominal pain, and jaundice because of the large size and malignant nature. Neurotensinomas remain rare and truly difficult to separate from the symptom complex produced by VIP excess. Edema, hypotension, cyanosis and flushing should alert one to the possibility of a neurotensin-secreting tumor.