Argon plasma coagulation is especially suited for thermal coagulation of tissue surfaces, for the haemostasis of surface bleeding and for the devitalisation of defined pathologic tissue layers. The maximum coagulation depth achievable under good control is 3-4 mm. Argon plasma coagulation has been tested successfully and is presently being used clinically in open surgery, especially for the haemostasis of surface bleeding in parenchymal organs. Consequently, the coagulation technique described here is gaining more and more interest in endoscopic surgery. The absence of the adhesion effect between the coagulation electrode and coagulum, of smoke production and of carbonization of the coagulum have played an important role in this development. There are already various applicators available for the endoscopic application of argon plasma coagulation. Their success is an encouragement to further development of this coagulation technique for endoscopic operations.