A variety of endoscopic methods are available as the main tools in the diagnostics and therapy of various complications after visceral and thoracic surgery. Indications for endoscopic interventions are anastomotic leaks, stenoses, Gl-tract bleedings, biliary lesions and functional problems after surgical procedures. The most common are fibrin sealing of fistulas, dilatation and bougienage, injection therapy for bleeding, bile duct interventions and stent implantations. In most cases operative revisions can be avoided by using endoscopic methods with an overall good success rate. No disadvantages are foreseen following conventional operative interventions if the endoscopic treatment is not successful.