Background: Sepsis continues to present a significant problem in the pediatric intensive care unit (PICU) worldwide. Sepsis in pediatric infants is an important cause of morbidity and mortality. The risk of sepsis increases with decreasing chronological age and weight. Objective: To identify of the risk factors of polymicrobial BSIs in pediatric patients with intravascular devices, via conducting the objectives, which were evaluating the frequency of monomicrobial and polymicrobial BSIs in pediatric patients. Patients and methods: This isobservational cross sectional study that was conducted in at PICU, General Zagazig Hospital, carried on 90 pediatric patients who were divided into 4 groups: group (I) oncology patients, group (II) cardiac patients, group (III) gastrointestinal (GIT) patients and group (IV) miscellaneous patients. Results: Our results showed that 50% of polymicrobial infection patients had cardiac disease, 25% had gastrointestinal disease. 25% had renal failure. 100% of the cardiac patients and the gastrointestinal patients had respiratory cause of admission to PICU. Conclusion: Steroids given to the patients, endotracheal intubation, central venous catheter (CVC), congenital heart diseases (CHD) and H2 blocker were the most common risk factors for polymicrobial infection in PICU.