Background and Aims.International studies revealed prevalences of around 50% of microbiological contaminations in reprocessed �exible endoscopes. In Germany a system was installed where the quali�cation for refund for colonoscopies was made conditional on successfully passing twice annually a microbiological surveillance test of reprocessed endoscopes. is study is an implementation and outcome evaluation as well as a general discussion of the quality assessment assurance in colonoscopy in Germany. Methods. German data from 2003-2008 were analysed: number of endoscopic units performing therapeutic and/or screening colonoscopies; results of all microbiological surveillance tests of reprocessing quality; number of failed surveillance tests and retests; number of quali�cations for refund from the public health system cancelled due to repeated failure of microbiological surveillance tests. Results. Aer the introduction of the quality assessment assurance, the percentage of failed microbiological surveillance tests dropped signi�cantly and steadily from close to 17% to below 5%. Conclusions. is study evidences (1st) the successful implementation of the quality assessment assurance in Germany and (2nd) a substantial improvement in the quality of reprocessing �exible endoscopes achieved by these measures.