BACKGROUND/AIMS: Carcinoid tumor of the rectum is relatively uncommon lesion with malignant potential, representing 17-27% of gastrointestinal tract carcinoid. The selection of treatment in rectal carcinoid tumor is determined by the depth of invasion and the presence of metastasis. In this study, we evaluated the clinical utility of EUS in selecting the management of the rectal carcinoid tumor. METHODS: Total 8 patients with rectal carcinoid tumor diagnosed by means of colonoscopy and EUS from 1994 to 1999 were included in this study. None had specific symptoms of carcinoid syndrome. The treatment modality of all tumors were selected by EUS before resection. We examined histologic feature after resection of tumors in order to evaluate the effectiveness of EUS. RESULTS: In total 8 patients, the image of tumors was oval to round. The internal echo was generally hypoechoic and homogenous. The margins were clearly visualized, and the contour was somewhat smooth. All tumor were resected completely. The overall accuracy of determining the depth of invasion using endoscopic ultrasonography was 87% (7 of 8 lesions). CONCLUSIONS: EUS is considered to be helpful in evaluating the malignant behavior of rectal carcinoid tumor. It is suggested that the criteria of the selection based on the EUS findings is available in the choice of treatment for rectal carcinoid tumor.