Of 480 patients admitted to the Pediatric Intensive Care Unit of the Institute of Child Health Children's Hospital in Istanbul, 97 required mechanical ventilation (MV). Sixty of these children were included in a retrospective analysis aiming to determine the frequency of and factors contributing to the development of nosocomial infections (NI). NI rate was 45 percent, ventilator-associated pneumonia (VAP) accounted for the greater part (66.7%) of the NI, followed by urinary tract infections (16.7%), septicemia (13.3%), and meningitis (3.3). Pseudomonas aeruginosa was the most frequent cause of VAP. The duration of the MV and invasive interventions were important risk factors for the development of VAP.