The aim of oncologic surgery is radical cancer treatment with preservation of function and quality of life. Almost 30 years ago, transanal endoscopic microsurgery (TEM) revolutionised the technique and outcomes of transanal surgery, first becoming the standard of treatment for large rectal adenomas, then offering a possibly curative treatment for early rectal cancer, and finally generating discussion on its potential role in combination with neoadjuvant therapies for the treatment of more invasive cancer. TEM afforded the advantage of combining a less invasive transanal approach with low recurrence rates thanks to enhanced visualization of the surgical field, which allows more precise dissection. We describe the current indications, the preoperative work-up, the surgical technique (with the aid of a video), postoperative management and results obtained in an over 20-year-long experience. Designed as an accurate means to allow excision of benign rectal neoplasms with a very low morbidity rate, TEM today is indicated as a curative treatment of malignant neoplasms that are histologically confirmed as pT1 sm1 carcinomas. T1 sm2-3 and T2 lesions should at present be included in prospective trials. Accurate preoperative staging is essential for optimal selection of patients. Patients with clear indication for TEM should be referred to specialized medical centres experienced with the technique.