Diphtheria has become a rare disease in Germany. We report on an unimmunized 3.5-year-old German girl with a 7-day history of respiratory distress and fever, presenting a clinical picture mimicking typical bacterial tracheitis without pharyngeal and laryngeal manifestation. Diagnosis of diphtheria was not made until culture of tracheal secretions yielded growth of a toxigenic strain of Corynebacterium diphtheriae. The patient died from toxic cardiac failure despite treatment with diphtheria antitoxin. This is the second reported case of isolated bacterial tracheitis caused by Corynebacterium diphtheriae.The observation of a lethal course of diphtheric tracheitis emphasizes the paramount importance of immunization against diseases like diphtheria.