Streptobacillus moniliformis is an uncommon human pathogen contracted from exposure to rodents. It usually produces a mild, protracted illness (rat-bite fever, Haverhill fever, erythema arthriticum epidemicum) that has either a favorable response to antibiotic therapy or spontaneously resolves. This report describes a fatal case of Streptobacillus moniliformis in an infant bitten by a wild rat. The autopsy findings included an interstitial pneumonia, fibrinous endocarditis, mild mononuclear meningitis, hepatosplenomegaly and lymphadenopathy, erythrophagocytosis, and sinusoidal mononuclear cell infiltrates in regional lymph nodes and the liver. To the authors' knowledge, this is the first report of the autopsy pathology findings of this agent.