Abstract: In the program-controlled cleaning of endoscopes in a cleaning apparatus, the head parts are cleaned, rinsed, disinfected and rinsed clean in pressure chambers and, at the same time, the insertion tubes are cleaned, rinsed, disinfected and rinsed clean in pipes, attached to these pressure chambers, in a number of cleaning stages using cleaning liquid which is introduced via a circulation pump at a pressure of approximately 200 mbar. Prior to each of these cleaning stages, compressed air generated in the compressed air unit of the cleaning apparatus is introduced from there through the pressure test attachment of each endoscope, which pressure test attachment is connected by means of a pressure test adaptor to a compressed air attachment of the cleaning apparatus, until an internal pressure of 250 mbar is reached.