[The importance of endoscopy in oncology]. 
The importance of the praetherapeutic histological manifestation of tumours is emphasized.  In many cases for this purpose an endoscopy with biopsy is necessary.  A particular role plays the endoscopy in urology, bronchology and gastroenterology.  The endoscopy significantly developed by the introduction of fully flexible glass fibre endoscopes.  This particular considers the gastroenterology.  Several regions, such as the duodenum, the small intestine and the colon, were thus first accessible to endoscopic biopsy.  Indications and possibilities of the individual endoscopic methods are mentioned.  As to the question, who individually should perform the endoscopy, the opinion is expressed that every specialist should perform the endoscopy in his field.  The performance of all endoscopic methods by one specialist, independent on the speciality, actually gives some technical advantages, which, however, do not compensate the disadvantages concerning a qualified total diagnostics of the diseases.  During the last years by the removal of the polyps the endoscopy in an increasing stage also becomes a therapeutic method.  At present the technical possibilities of endoscopy came to a certain close.  By all means necessary is, however, the further distribution of the endoscopic methods which depends on the availability of adequate endoscopes.