Eucalyptus camaldulensis Dehnh. is regarded to possess various medicinal properties such as anesthetic, antiseptic, astringent and anti diabetic, but there are few studies on its antibacterial effects. In the present study antibacterial activity of E. camaldulensis on 100 Multi Drug Resistant isolates of S. aureus, A. baumannii, P. aeruginosa, K. pneumoniae and E. coli were evaluated. E. camaldulensis samples were collected from the fi elds of Urmia in Northwestern Iran. Plants were cut, and powder was prepared. Powdered plants were extracted by maceration at room temperature for 72 hours. Bacterial isolates were collected from clinical specimens of different wards of educational hospitals in Urmia, Iran during a 12-month period. The susceptibility of isolates to E. camaldulensis extracts was determined using a broth microdilution method. Considering to the wide application of ciprofl oxacin in treatment of bacterial nosocomial infections, the antibacterial effects of ciprofl oxacin on isolates was also determined. All the multi-drug resistant bacterial isolates were sensitive to different concentrations of E. camaldulensis hydro-alcoholic extract. The most sensitive bacterial isolates to E. camaldulensis extracts were P. aeruginosa isolates, although 69% of isolates were resistant to ciprofl oxacin. Results demonstrated that this herbal drug may represent a new source of antimicrobial agent for controlling the hospital acquired infections. However, studies that are more adequate must be carried out to verify the possibility of using it for fi ghting these bacteria in human infections