In this study the quality of endoscope reprocessing was examined in 60 samples of different gastroscopes routinely used in major university hospital in Germany. The reprocessing of the endoscopes was based on the KRINKO recommendation for flexible, thermolabile endoscopes (1) and consisted of the following steps: cleaning at the light source, manual pre-cleaning, cleaning and disinfection in the automated endoscope reprocessor (AER). Manual pre-cleaning was performed with conventional reusable brushes and the pH-neutral cleaner Bodedex® forte. The endoscopes were evaluated using a measurement of adenosine triphosphate (ATP) and microbiological controls of rinse samples. After cleaning at the light source, the mean ATP value was 19,437 relative light units (RLU), after brush cleaning it was 667 RLU, and after reprocessing in the AER it was 227 RLU. Measured by colony-forming units (cfu), the mean number per endoscope after brush cleaning was 15.3 cfu/10 ml and after reprocessing in the AER was 5.7 cfu/10 ml. Overall, not all reprocessing steps were able to ensure complete cleaning. Therefore, close routine control is recommended and the ATP bioluminescnece methode is a good and fast way to do it.