Hospitals are the places where, either the patients or other health workers can encounter with dangerous problem of several bacterial, fungal, viral, parasitic infectious agents, especially the emerging and life threatening ones such as, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus faecalis (VRE), Stenotrophomonas sp., and multi drug resistant Acinetobacter sp., Pseudomonas sp.. The reasons of these resistant microorganisms that can threaten the life of patients and hospital personnel are the floor, the surface areas, the clinical equipments, the medical and dental devices, and the dental unit water lines in hospitals, which might be a reservoir for them and may cause to cross-infections among patients and other people. Hospital infections bring about prolonged hospital stay length, increased mortality and morbidity rate, cost rise, labor loss, deterioration in quality of life, adverse effect on the doctor’s success, and disruption in the treatment of patients. Therefore, disinfection processes in medical and dental hospitals against to the agents play a key role to form safe and clear environment and avoid the infections causing to failure in treatments