A fatal case of Waterhouse-Friderichsen syndrome resulting fromEwingella americanainfection in a previously healthy 74-year-old woman is reported. The patient died suddenly within 14 hours after presentation. The diagnosis of Waterhouse-Friderichsen syndrome as the cause of death was established post mortem based on autopsy findings, microscopic examination, measurement of serum procalcitonin concentration (113 ng/ml), and outcome of postmortem bacteriologic cultures that grewE. americanain heart and spleen blood samples. Since the introduction ofE. americanaas a new group in the familyEnterobacteriaceaein 1983, more recent case studies have established its clinical significance and pathogenic potential to cause severe, life-threatening bacteremia and sepsis.E. americanais a rare pathogen that should be added to the list of unusual bacteria causing Waterhouse-Friderichsen syndrome.