Carcinoid tumors are new growths from neuroendocrine cells. The following clinical variants of carcinoid were observed in 11 patients with histologically verified carcinoid: 1) asymptomatic variant (an occasional finding at endoscopy)--2 cases; 2) carcinoid with symptoms of a mass detected at surgery--2 cases of intestinal ileus, 2 cases of appendix carcinoid simulating acute appendicitis; 3) carcinoid with hepatic metastases and carcinoid syndrome with unknown primary focus--2 cases; 4) carcinoid with metastases to the liver and carcinoid syndrome with location of the primary tumor in the lungs (2 cases) and pancreas (1 case). It is stated that carcinoid tumors are encountered more frequently than diagnosed (0.1-0.5% of all the tumors). Manifestations of carcinoid syndrome allow to diagnose carcinoid only at late stage when a large mass of hormone-active tumor tissue and metastases to the liver are present.