Coincident with medical antitumor treatment of 138 patients suffering from mid-gut carcinoid tumors, 51 patients were subjected to surgery with the principal aims of removing primary tumors and debulking mesenteric or liver metastases. Sixteen patients had previously been operated with intestinal resection or, when the tumors had been considered inexcisable, with intestinal bypass or laparotomy alone. Apart from exhibiting symptoms related to the carcinoid syndrome, the majority (approximately 60%) of the 51 patients had generally intermittent, subileus-like abdominal pain and weight loss. In 18 patients, these symptoms were pronounced and associated with intestinal obstruction or severe malnutrition. Computed tomography and arteriography efficiently demonstrated mesenteric and liver metastases. At laparotomy, the primary intestinal tumors were small, mainly less than 1 cm in diameter, and they were multiple in 39% of the patients. Mesenteric metastases measuring up to 12 cm in diameter were present in 86% of the patients. These metastases were frequently associated with a pronounced mesenteric and retroperitoneal fibrosis causing fixation, angulation, and obstruction of the bowel as well as incipient intestinal gangrene in 8 patients. In all but 6 patients, the primary tumors could be removed by comparatively limited intestinal resections although bulky mesenteric metastases were often dissected from the mesenteric vessels. Liver metastases, found in 49% of the patients, were generally bilateral and multiple, and major hepatic metastases were resected in 6 patients. The results support a role for surgery also in the more compromised patients with mid-gut carcinoid tumors and that such intervention may be associated with considerable symptomatic relief and substantial periods of survival.