Several factors are implicated in the increased vulnerability of multiple trauma victims to infection, especially in intensive care-units (ICU). This cohort study was designed to report the incidence, the topography, the etiology and to identify the risk factors for infection in trauma patients admitted in an ICU. From January 2000 to December 2001, 416 trauma patients were admitted to the ICU for more than 24 hours, the mean length of stay was 9.3 days (range 2-65) and 188 (45%) patients developed a total of 290 NI. The most prevailing infections were pneumonia (49%), bloodstream (19%) and urinary tract infections (12%). The variables studied were: the demographic data, diagnosis on admission, site and mechanism of injury, type and number of surgeries, use of invasive devices, days under mechanical ventilation (MV) and site and number of NI. These variables were analyzed with a univariable and multivariable regression analysis. The NI was associated with injury in more than 1 anatomic segment (OR=1.6; CI95%1.06-2.40); mechanical ventilation for more than 3 days (OR=12; CI95% 6.87-24.02); more than 1 surgery (OR=3.13;CI95%1.75-5.65) and more than 2 invasive devices (OR=4.7; CI95%2.99-7.37). Deaths over the first 5 days had high association (RR=3.18) with NI. Three significant variables were identified in the logistic regression, which are: more than 3 days under MV, number of invasive devices and number of surgeries.