The genus Aeromonas contains some species that are potential human pathogens. These Aeromonas species are known to posses up to three different classes of chromosomal beta-lactamases. The production of beta -lactamases is one of the main causes of treatment failure. We used whole genome sequence analysis to identify our samples to the species level, previously identified by MALDI-ToF, and to characterize the chromosomal beta-lactamases of seven different Aeromonas species. We found some beta-lactamases to be species-specific and we also found differences in the number of beta-lactamases associated to each species.