AIM: To assess the results of endoscopic mucosal re-section with a ligation device (EMR-L) combined with three dimensional endoscopic ultrasonography (3D-EUS) using an ultrasonic probe for rectal carcinoids. In addition, diagnosis of the depth and size of lesions by EUS was evaluated. METHODS: Between January 2003 and March 2007, 20 patients underwent EMR-L with 3D-EUS using an ultrasonic probe (group A). 3D-EUS was combined with EMR-L at the time of injection of sterile physiological saline into the submucosal layer. For comparison, 14 rectal carcinoids that had been treated by EMR-L with-out 3D-EUS between April 1998 and December 2002 were evaluated as historical controls (group B). EUS was conducted for all of the patients before treatment to evaluate tumor diameter and depth of invasion. The percentage of complete resection and the verti-cal resection margin were compared between the two groups. RESULTS: The depth of invasion upon histopathologi-cal examination was in complete agreement with the pre-operative fi ndings by EUS. The tumor diameter de-termined by EUS approximated that found in the tissue samples. There were no signifi cant differences in the gender, tumor sites or tumor diameters between the two groups. The rate of complete resection for groups A and B was 100% and 71%, respectively (P < 0.05). The vertical resection margin of group A was longer than that of group B. CONCLUSION: EMR-L is effective as an endoscopictreatment for rectal carcinoids. In combination with 3D-EUS, safe and complete resection is further as-sured. AIM: To assess the results of endoscopic mucosal re-section with a ligation device (EMR-L) combined with three dimensional endoscopic ultrasonography (3D-EUS) using an ultrasonic probe for rectal carcinoids. In addition, diagnosis of the depth and size of METHODS: Between January 2003 and March 2007, 20 patients underwent EMR-L with 3D-EUS using an ultrasonic probe (group A). ​​3D-EUS was combined with EMR-L at the time of injection of sterile EUS was conducted for all of the patients before treatment to evaluate the tumor diameter and depth of invasion. The percentage of complete resection and the verti-cal resection margin were compared between the two groups. RESULTS: The depth of invasion upon histopathology-cal examination was in complete agre The tumor diameter de-termined by EUS approximated that found in the tissue samples. There were no signifi cant differences in the gender, tumor sites or tumor diameters between the two groups. The rate of Complete resection for groups A and B was 100% and 71% respectively (P <0.05). CONCLUSION: EMR-L is effective as an endoscopictreatment for rectal carcinoids. In combination with 3D-EUS, safe and complete resection is further as-sured.