Transanal endoscopic microsurgery (TEM) is a minimally invasive technique affording full-thickness resection of rectal tumors and can also be used as a platform for transrectal access to the peritoneal cavity for NOTES (natural orifice transluminal endoscopic surgery) procedures. The authors investigated the anatomical characteristics of the pelvis in Koreans to develop an ergonomically designed NOTES platform. A total of 256 patients (156 men and 100 women) who underwent pelvic magnetic resonance imaging for evaluating rectal neoplasms were enrolled for analysis. The authors retrospectively reviewed and calculated anatomical lengths and angles on pelvic magnetic resonance images and analyzed differences in pelvic anatomy in terms of patient gender, age, and body mass index. Various angulations were noted from the anal canal to the sacral promontory, attributable to the shape of the sacral bone. Minimal difference in pelvic anatomy was evident between men and women. In conclusions, the authors expect that their data will be useful in the development of ergonomic TEM-NOTES platforms.