In this article we intend to describe the epidemiological profile of nosocomial infection in pediatric patients with multiple trauma. We conducted a prospective study from July to November 2003 in a pediatric teaching hospital in Barcelona. We used US Centers for Disease Control and Prevention standard criteria to define nosocomial infection. Of the 121 patients included in the study, 33% had at least one episode of nosocomial infection, with an incidence rate of 9.9 infections per 100 admissions and 1.1 infections per 100 patient-days. The most frequent episode of nosocomial infection was bacteremia. Coagulase-negative staphylococci were the most common pathogens. Nosocomial infection rates per 100 device-days were 3.2 for bacteremia, 1.6 for respiratory infection and 1.0 for urinary tract infection. These findings suggest the need to evaluate infection control measures aimed at reducing the morbidity associated with infections.