The potential advantages of ultrasound dissection using UltraCision (UC), an ultrasonically activated scalpel, rather than conventional electrosurgery (ES) were investigated retrospectively in 63 patients following transanal endoscopic microsurgery (TEM) in 22 cases of rectal carcinoma (16 pT1, four pT2, two pT3), 40 cases of rectal adenoma >2 cm, and one neurinoma. In all, 21 patients (13 adenomas, seven carcinomas, and one neurinoma) were operated with UltraCision (Ethicon, Norderstedt, Germany), whereas 42 patients (27 adenomas, 15 carcinomas) were treated with conventional electrocautery. All tumors were completely excised (R0) in both groups. We encountered a total of nine complications, seven after ES and two after UC use. Surgical reintervention was necessary in three cases (4.7%), exclusively following resection by ES. There were five cases of tumor recurrence (7.9%), once again only in the ES group. The advantages of ultrasound dissection are magnified under the particular conditions of minimally invasive endoscopic rectum surgery by means of TEM. In principle, all the known risks associated with the application of electric current can be avoided by using ultrasound technology.