Ventilator - Associated Pneumonia (VAP) is a common complication in patient who is on ventilator with the prevalence rate of 50 percent. It also impacts on hospitalized duration, treatment cost as well as mortality. Subject: Initially analysis the etiologies of ventilator - associated pneumonia and evaluation effectiveness of the method using continuous aspiration of subglottic secretions for patients who were on mechanical ventilation. The goals: To evaluate effectiveness of the method using continuous aspiration of subglottic secretions in preventing from ventilator-associated pneumonia. Objects and method: from 9/2009 to 9/2010 at the Emergency Department and ICU Bach Mai hospital, there were 25 patients who had met all the criteria selected to the study and the patients were divided into two groups: 12 patients who were randomized to receive continuous aspiration of subglottic secretions called the study group, and the other 13 patient were involved in the control group with the conventional care. The results: The most of causes were Acinobacter baumaniae (account for 5 of 9 patients in both groups), the second were Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus respectively. The ratio of VAP in the study group was 25 percent versus 46,2 percent in the control group (p0.05). There were significant reduction of VAP (RR