The level of procalcitonin is undetectable in healthy individuals and slightly increased in viral infections and noninfectious inflammatory responses. It has been described to be notably increased in bacterial, parasitic, or fungal infections. Procalcitonin has been reported to be a reliable marker for severe bacterial infections, although it has mainly been studied in specific entities or in selected groups of patients. We prospectively determined the procalcitonin level in 103 unselected febrile hospitalized patients. Most of them had a proven (39) or probable bacterial infection (44). Procalcitonin was more frequently positive in bacteremic patients (p = 0.01), in patients with a proven bacterial infection (p < 0.01), and in those with a high sepsis score (p < 0.005), however; when cases with proven bacterial infection were considered as a reference, the sensitivity of the test was only 54% and the specificity 70%. Procalcitonin determination should not be included systematically in the screening of febrile hospitalized patients.