The present study reports the first case of fatal Acinetobacter baumannii infection in the critically endangered European mink (Mustela lutreola). Gross examination revealed a severe, diffuse hemorrhagic pneumonia and generalized congestion as main features. Microscopically, the main lesions were an acute, severe fibrinous–hemorrhagic pneumonia associated with proliferation of coccobacilli and generalized acute–subacute congestion. Cultures yielded A. baumannii; the species was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the strain presented a multidrug-resistant pattern. The results are not only of conservation concern but also of public health concern given A. baumannii is one of the most important pathogens implicated in nosocomial infections in humans.