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.