Procalcitonin (PCT) is a frequently used marker for bacterial sepsis. The present study was aimed to assess the usefulness of PCT measurement in patient with sepsis. We studied the relationship between serum PCT level and blood culture in clinical 209 cases admitted from January 2010 through June 2010. We compared PCT level with blood culture results and other clinical data, and diagnosis such as sepsis and systemic inflammatory response syndrome (SIRS) were obtained from the medical records. In the case of patients with positive blood cultures and PCT < 0.5 ng/mL, the false- positive blood culture was suspected. The possibility of bacteremia was high when PCT level was more than 0.5 ng/mL. Patients with PCT ≥ 2 ng/mL had significant correlation with the presence of sepsis. The PCT measurement could be performed and reported rapidly and provided valuable information before availability of culture results. In this study, we found that the PCT would be a useful biomarker for confirming and ruling out sepsis.