Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is a facultative anaerobic Gram-negative coccobacillus that is associated with a variety of diseases in humans. In the present study, the isolate finally identified as A. actinomycetemcomitans by MALDI-TOF was misidentified as Pasturella canis or Pasturella multocida by the automated VITEK 2 system. The findings re-enforce the importance of an accurate and rapid diagnosis to assist patient management.