Antibiotics and chemotherapeutics with antibacterial activity are currently indispensable in veterinarymedicine. The emergence of antimicrobial resistance poses a threat to the health of both humans andanimals and to the animal food production as we know it today. The current review clarifies some basicterms and concepts with regard to antimicrobial resistance. Moreover, a summary is provided of howresistance can be determined and how the results of susceptibility testing should be interpreted.