The authors studied bacteriological characteristics in 63 patients with ventilator associated pneumonia (VAP), treating at the intensive care unit (ICU) of Hospital No.103, from 01/2009 to 12/2011. The results showed that: The bacteria are mainly Gram-negative bacilli: 79.31 percent, Gram-positive bacteria: 20.69 percent. P.aeruginosa is resistant to most antibiotics, only sensitive to imipenem, ticarcilline/clavulanate. E. coli resistant to Ampicilline, amoxicilline, cefotaxime (84.61 percent). There is E.coli resistant to imipenem and ertapenem (7.69 percent). S.aureus is totally resistant to gentamycie, Kanamycine, amikacine, oxaciline and noftoxacine, but S.aureus still is sensitive to vancomycin. Pneumoniaonset ventilator met mainly Gram-negative bacteria accounting for the majority: 72.42 percent, common: P.aeruginosa, K.pneumoniae, E coli, S. aureus ...