Intracavitary microwave coagulation for bladder cancer has been performed in our department. Transabdominal sector scanning gave us useful informations during microwave coagulation procedure. In this method, we were able to confirm the position of microwave radiator, bladder wall and bladder tumor even if cystoscopy did not make it possible to find the tip of the microwave radiator. During this procedure, we could observe the microwave radiator clearly which had a hyperechoic area and an acoustic shadow. We were able to perform intravesical management without complications using the electronic sector scanning. We report the usefulness of this method here.