Transanal endoscopic microsurgery (TEM) has revolutionized the technique and outcomes of transanal surgery, becoming the standard of treatment for large sessile rectal adenomas, and may represent a possible treatment modality for early rectal cancer.A full-thickness excision is made on the rectal wall down to the perirectal fatty tissue. The specimen is retrieved transanally. After the parietal defect is disinfected, the wound is closed with one or more running sutures secured with silver clips.Peritoneal perforation during TEM is not associated with adverse short-term or oncologic outcomes. The postoperative morbidity rate ranges between 2 % and 15 %, and in most cases, complications can be conservatively managed. The local recurrence rate of large adenomas is about 6 %, and most recurrences can be safely re-resected by TEM. TEM represents an effective treatment for pT1 sm1 rectal malignancies, while pT1 sm2-3 and pT2 should be considered at high risk of recurrence if treated by TEM alone. Finally, TEM does not influence anorectal function or quality of life.TEM is a safe procedure and provides excellent functional and oncologic outcomes in the treatment of large sessile benign rectal lesions and selected early rectal cancers.