Thirty five bacterial isolates were collected from urine and blood samples of 20 patients, before and after endoscopy examination, in new Surgical Hospitals, Zagazig University Hospital, Zagazig, Egypt. Antibiotic susceptibility profile of purified bacteria revealed four multi-resistant strains identified as S. aureus Zag11, P. aeruginosa Zag60, E. coli Zag126 and S. epidermidis Zag128. The four selected bacteria were subjected to some disinfectants (glutaraldehyde, hydrogen peroxide, P3-oxonia and Orthophthaladehyde) at different concentrations and different exposure times. It was observed that 10 min were enough to inhibit growth of tested pathogenic bacteria in case of (8% H2O2 & 0.55% orthophthaladehyde) while completely inhibition was recorded after 15min in case of ( 2.2% glutaraldehyde, 70% ethanol and 0.45% P3-oxonia). Sterile urinary tract endoscopy was artificially contaminated with mixture (1:1:1:1:1:1) of six clinical pathogenic bacterial strains pararil with the four tested bacterial strains. Upon exposing the contaminated endoscope to different chemical disinfectants; 8% hydrogen peroxide and 0.55% Orthophthalaldehyde inhibited after 30 min exposure while 2.