The diagnostic power of procalcitonin (PCT) in the pediatric intensive care unit (PICU) is uncertain. This study aimed to determine the diagnostic ability of PCT to detect serious bacterial infections (SBI) in a heterogeneous PICU population. This was a retrospective cohort study of patients on whom a PCT level was obtained within 48 hours of admission to a PICU from 2013 to 2015. Discriminatory ability of PCT to predict SBI was examined by test and receiver operating characteristics (AUC [area under the curve]-ROC). Seventy-five patients were included and 28 (37%) had an SBI (median PCT = 6.48 ng/mL) compared with 47 (63%) in the noninfection group (median PCT = 0.23 ng/mL, P < .0001). PCT was able to adequately predict SBI (AUC-ROC = 0.83, 95% CI 0.74-0.93; P < .0001), and a PCT ≥1.28 ng/mL was the optimal threshold to detect SBI with a positive predictive value of 76.7% and negative predictive value of 88.9%. PCT adequately predicted SBI in a heterogeneous PICU population and may be useful for minimizing antibiotic consumption.