Objective: Sepsis is a life-threatening condition associated with high morbidity and mortality. Critically ill patients often show Systemic Inflammatory Response Syndrome (SIRS), independent of infection. This study evaluates diagnostic and prognostic value of blood Procalcitonin (PCT) in pediatric bacterial septicaemia. Methods: 150 ICU-admitted septic children and 50 healthy age- and sex-matched controls were sampled at admission (T0), 24 h (T24), and 96 h (T96). PCT > 0.5 ng/ml was positive. Results: 63% of bacterial cases had detectable PCT at higher concentrations; viral cases only 22.2% at lower concentrations. Mean PCT reduction: bacterial 44.39 ± 41.82%, viral 5.71 ± 26.68%. Conclusion: PCT levels are a reliable marker for bacterial infections and can guide antibiotic therapy in critically ill children. © 2013 Elsevier B.V., All rights reserved.