We evaluated whether procalcitonin (PCT) might aid diagnosing serious bacterial infections in a general pediatric intensive care unit population. Two-hundred and one patients accounted for 332 PCT samples. A PCT ≥1.45 ng/mL had a positive predictive value of 30%, a negative predictive value of 93% and a sensitivity of 72% and a specificity of 75%. These data suggest PCT can assist in identifying patients without serious bacterial infections and limit antimicrobial use.