We reviewed 28 cases of carcinoid tumor arising in the small intestine (11 cases), appendix (eight), rectum (three), and lung (six), which were diagnosed during a ten-year period ending in 1977. Components of the carcinoid syndrome occurred in only three patients, all of whom had hepatic metastases from tumors of the small bowel. Most of the small intestinal lesions, which usually were multicentric, metastasized. When metastases were absent or confined to regional lymph nodes, surgical excision alone provided satisfactory long-term therapy. When the disease involved the liver, the course until death was usually long but inexorable unless chemotherapy was used. During follow-up, which averaged more than six years, no carcinoid of the appendix, rectum, or lung recurred or metastasized after surgical extirpation. Other neoplasms, including adenocarcinomas of the rectum, appendix, prostate, and nasopharynx and acute granulocytic leukemia, appeared in six patients, which extends previous observations that patients with carcinoids have a neoplastic diathesis.