Objectives: Procalcitonin (PCT) might be a useful marker to exclude bacteremia or to predict the severity of bacteremia and its outcome. However, most previous studies of PCT were limited to particular patient populations. In addition, reports about PCT levels in patients with renal dysfunction have been conflicting. We investigated the predictive value of PCT in an unselected population with suspected bloodstream infections and also assessed the relationship between PCT and renal function. Methods: We retrospectively analyzed medical records of 1,331 patients (age ≥1 8 years) with suspected bloodstream infections who had concurrent biochemical data and blood culture results. Results: The PCT level was significantly elevated in patients with positive blood cultures, and it showed a significant relation with survival in patients with bacteremia. The optimal cutoff value of PCT for predicting a positive blood culture showed an increase as the estimated glomerular filtration rate declined. Conclusion: PCT can be a useful marker to exclude bacteremia and also to predict severe bacteremia, but renal function should be taken into account.