Transumbilical single-port laparoscopy has emerged as a method to further enhance cosmetic benefits and reduce morbidity. We present an initial experience with transumbilical laparoendoscopic single-site partial nephrectomy (LESS-PN). A 36-year-old woman visited our hospital for the treatment of a left exophytic renal cell carcinoma, 17 mm in diameter, located at the lower pole. We decided to use transumbilical LESS-PN to treat this case. A multichannel port was placed through the center of the umbilicus, and the tumor was exposed using bent laparoscopic instruments. The tumor was then removed after microwave tissue coagulation. All procedures were performed without renal artery occlusion, and only slight bleeding occurred. Transumbilical LESS-PN using a microwave tissue coagulator was performed with an excellent cosmetic outcome and no complications. To the best of our knowledge, this is the first report of LESS-PN using a microwave tissue coagulator.