A new endoscopic surgical method was developed for removal of large sessile adenomas of the rectum and lower sigmoid. Stereoscopic sight and magnifying glasses do allow precise surgery of these tumors. If adenomas are present they can be removed using the technique of mucosa excision; if on the other hand rectum carcinomas have to be removed the complete wall of the rectum in an appropriate extension can be excised. Hemorrhages which occur during preparation always can be stopped by diathermy. The surgical intervention is terminated by a transverse continuous suture of the defect. 33 patients were operated upon in this way from July 1983 to April 1985. Areas with an diameter of up to 10 cm could be removed, even located up to 18 cm in the colon. Suturing of the defect could always be performed without problem. In 1 patient a relapse occurred.