Quality assurance in gastrointestinal endoscopy, as a crucial diagnostic and therapeutic process in medical care, has become a matter of increasing interest. However, concrete measures and standards are still lacking. Quality assurance as "continuous improvement" and "improvement by inspection" are discussed. Examples for clinical measures in the fields of indication for endoscopy, accuracy to the diagnostic test, thoroughness of the procedure and assessment of complications are given, and educational problems are discussed. Such structural problems of quality assurance as handling of a vast amount of data and assessment of late complications by follow-up information are addressed. Electronic data processing seems to be the most economic way to solve these problems. Requirements to data processing in the view of quality assurance are defined. Transferral of data from other departments within a hospital information system is necessary for the assessment of long-term follow-up. Different methods of communication within a hospital information system are discussed.