Ventilator-associated pneumonia (VAP) is the most commonly-acquired infection in patients in intensive care units. We analyzed epidemiological and microbiological characteristics and the outcome, in a cohort of critically-ill patients with confirmed diagnosis of VAP. All patients who had been on mechanical ventilation (MV) for more than 48 hours were included in our study; material collection for microbiological analysis was done within the first 24 hours after beginning treatment or after changing antibiotics. There were 55/265 (20.7%) VAP cases diagnosed, at a rate of 21.6 episodes per 1,000 days of mechanical ventilation. Mean age of the patients was 66 years, with a mean APACHE II score of 26.7 + 7.0; male patients were more prevalent. The mortality rates in the intensive care unit (ICU) and during the hospital stay were 71% and 80%, respectively. MV duration in patients with VAP was 17 (range 3-43) days and among patients who had not developed VAP, 6 (2-32) days (p < 0.0001). 98.2% of the samples were positive, with a high prevalence of Gram-negative bacteria, mainly Acinetobacter calcoaceticus. Risk factors for death included age, MV duration and surgery. VAP incidence in this sample of critically-ill patients was high, with a high mortality rate. Control and prevention strategies based on continuing education of healthcare workers, developed by a multidisciplinary team, should be encouraged to minimize morbimortality of this infection.