Background & Aims: Little is known about the prognosis of patients with malignant digestive endocrine tumors (MDETs), primarily because of their rarity. Methods: Survival from these tumors has been evaluated in a large, well-defined, national population. All patients diagnosed and registered in England and Wales during the 14-year period from 1986 to 1999 were followed up for vital status to the end of 2001. Relative survival was estimated and the impact of age, sex, period, histology, and anatomic site modeled. Results: Among 4104 cases of MDETs, 21.2% were small cell tumors. Relative survival for all MDETs combined was 45.9% at 5 years and 38.4% at 10 years. Five-year survival was 56.8% for well-differentiated tumors but only 5.2% for small cell tumors ( P < .0001). Survival was highest for large bowel tumors and lowest for esophageal tumors. Among well-differentiated pancreatic tumors, 5-year relative survival was 49.2% for insulinomas, 39.9% for gastrinomas, 17.1% for glucagonomas, 26.3% for carcinoid tumors, and 29.3% for nonfunctioning tumors. There was no difference in survival between socioeconomic groups. Five-year survival did not improve between 1986 and 2001. Survival was higher for women and for younger patients. Gender, age at diagnosis, and anatomic site were independent prognostic factors. Conclusions: The prognosis of patients with MDETs in the general population is considerably worse than is often reported from small hospital case series. Prognosis varies with tumor differentiation, anatomic site, and histologic type. Early diagnosis is difficult; new therapeutic options appear to represent the best approach to improved prognosis.