Because of its advantages as small unit size, portability, and low cost, the diode laser is expected to come into wide use in laser therapy. We evaluated the ability of the diode laser in the treatment of superficial bladder pathology. To have vaprization abilites, we attempted to use diode laser with indocyanine green (ICG) pretreatment. The medical diode laser system (DIOMED25, Diomed Company, UK) was used with 25W at 805nm. The applied output power was 5W and was delivered to the tissue through a flexible silica glass fiber. Bladder of anesthatized dog was used. The irradiation was performed in the noncontact mode with a spot diameter of 2mm. To assess the enhancement effect of indocyanine green (ICG), ICG solution (1mg/ml, 0.3ml) or normal saline was injected submucosally immediately before the irradiation. The temperature at the subadventitial layer was measured with a needle type thermocouple and the intensity of transmitted laser which passed through the whole layer was evaluated by a laser power meter. After observing the macroscopic appearance of the bladder surface, the specimen was kept in 10% formalin for histological consideration. With ICG pre-injection, vaporization and coagulation of the mucosa was obvious within 10 seconds and the whole mucosal layer was vaporized in 40 seconds. The subadventitial temperture measurement revealed that the temperture increase in the subadventitial layer is reduced by the ICG pretreatment. The transmitted of laser did not increase by the ICG pretreatment. Our results suggest that the diode laser with ICG pre-injection can be used to vaporize and coagulate the superficial pathology of urinary bladder more selective and safer.