To assess the outcomes of transanal endoscopic microsurgery in small (Ͻ3 cm), large (3-5 cm), and giant (Ͼ5 cm) lesions and compare these with reports of alternative techniques. Design: Data from January 1998 to February 2010 were prospectively collected. Lesions were divided into 3 groups according to the maximum diameter (group A, Ͻ3 cm; group B, 3-5 cm; and group C, Ͼ5 cm) and outcomes were analyzed separately. Setting: Colorectal unit in a single-district general hospital. Patients: Patients diagnosed as having benign rectal adenomas.