Abstract: Corynebacterium pseudotuberculosis and Corynebacterium ulcerans are recognized as a veterinary pathogen and causing considerable economic impact due to the inefficacy of antimicrobial therapy. Diphtheria toxin can cause myocardial and neurological damage and diphtheria toxin gene detection is considered as a suitable procedure for determining the toxigenicity of corynebacterial isolates. Because there are few studies examining Corynebacterium in duck, researchers evaluated the incidence, toxigenicity and antibiotic susceptibility of Corynebacterium strains from moribund ducks in South Korea. In addition, researchers performed Direct Genome Restriction Enzyme Analysis (DGREA) for the subtyping of Corynebacterium strains. A total of 15 C. pseudotuberculosis strains and 2 C. ulcerans strains were identified using the Vitek System®2, PCR amplification and 16S rRNA gene sequencing. All of the strains used in this study possessed the diphtheria toxin gene. Additionally, the results of antibiotic susceptibility testing showed that 15 of the 17 strains exhibited resistance to multiple antibiotics. In this study, DGREA yielded results that were dependent on the isolation area which could be useful for tracing the source of infection and indicate the potential application of this technique in disease prevention and disinfection.