ABSTRACT 
 
Background: Multiple Organ Dysfunction Syndrome (MODS) has been a significant cause of mortality in critically ill children. There is an urgent need for an excellent biomarker to accurately determine the prognosis of critically ill children on ICU admission for its high morbidity and mortality rate. This study is aimed to identify the association between serum procalcitonin and the severity of organ dysfunction. 
 
Subjects and Methods: A cross-sectional study was conducted in PICU and HCU at Dr. Moewardi Hospital from August 2020 to May 2021. The target population is pediatric patients (1 month – 18 years) with suspicion of infection. A sample of 25 children was taken using purposive sampling. The dependent variable is the severity of organ dysfunction, assessed by the PELOD-2 score. The independent variable is serum procalcitonin, measured by the ELFA method. Data were analyzed by using Spearman’s rank correlation, multiple linear regression, and ROC curve. 
 
Results: Serum procalcitonin value is significantly associated with severity of organ dysfunction (? = 0.42; p = 0.043). Critically ill children with serum procalcitonin value > 11 ng/ml have higher risk for severe or moderate organ dysfunction (RR = 2.20; 95% CI = 1.15 – 4.24). 
 
Conclusion: There is evidence that the higher value of serum procalcitonin is associated with more severe organ dysfunction in critically ill children. Thus, this biomarker could be used to determine the prognosis of patients on ICU admission. 
 
Keywords: serum procalcitonin, organ dysfunction, children