Transanal Endoscopic Microsurgery (TEM) was clinically introduced by Buess et al. In 1983 for the removal of adenomas from the rectal cavity. Later, the indications were extended to the excision of pT1 low-risk carcinomas in curative and to tumors in higher stages in palliative intent. Training courses for this method have been conducted since 1985 and several hundred surgeons have been taught this procedure in Germany and other countries. Because TEM is gaining international recognition it is worthwhile to review the complications of the method.