Stenotrophomonas maltophilia-associated infection is increasingly recognized as an nosocomial infection which occurs, in immunosuppressed individuals but not exclusively. Many strains of the bacterium manifest resistance to multiple antibiotics. It is considered an environmental bacterium, although little is known of the epidemiology of S. maltophilia, its sources and reservoirs. Even less is known of pathogenic mechanisms and virulence factors and this, reflects over difficulties in distinguishing colonization from true infection, which has fostered the view that the bacterium is essentially non-pathogenic.This study is generaly case report of unusual isolation of originated from medical devices (endotracheal tubes) used to support immunosuppressed surgical patients in KARIL and attempt to distinguish colonization from infection. During our continious monitoring procedure in KARIL, we have isolated 9 multi-drug resistant strains of Stenotrophomonas maltophilia (100% resistance to cefixime, ceftriaxone, cefuroxime, cefotaxime, coamoxiclav,imipenem). Automatic VITEK technique has been used for identification as well as for antibiotik susceptibility testing, to confirm traditional microbiological tecniques (morphology of colonies on blood agar plates and positive oxidase test,diskdifussion method and E-test).All patients suffered from traumatic haemoragical shock syndrome. Clinical significance has been confirmed in 2 cases with clinical signs for lower respiratory infection (high body temperatute 38.5oC, and Ro confirmation). These patients have been treated with clindamycin and ceftriaxone with recovering period in 4 days. Keywords:Stenotrophomonas maltophilia, ICU, clinical significance, endotracheal tube