A surgical resection in the middle or upper region of the rectum is often technically difficult because of the anatomical inaccessibility of the site. A new rectoscopic operative technique reported by Buess et al. (1985, 1987, 1988) and Kipfmüller et al. (1988) permits microsurgery in the rectum and is less aggressive than other procedures. This technique was used in 7 patients with rectal tumors using an articulated monocular-optical system. The postoperative course in all patients was free from any complications and the patients were discharged at the latest on the eighth day after the operation. A stereoscopic optical system, a new surgical rectoscope, other special surgical instruments, as well as a modification to an insufflation device are necessary for improving the endoscopic operation.