Rabies virus (RABV), canine distemper virus (CDV), canine parvovirus type-2 (CPV-2), and canine influenza A virus (CIV) are important contagious pathogens in canine populations. To assess post-vaccination immunity against RABV, CDV and CPV-2, and serological evidence of exposure to influenza A virus in military working dogs (MWDs) in Korea, we tested blood samples of 78 MWDs by fluorescent antibody virus neutralization (FAVN) for RABV, and by commercially available enzyme-linked immunosorbent assay (ELISA) for CDV, CPV-2, and CIV. Korean MWDs had high antibody-positive rates against RABV (97.4%, ≥0.5 IU/ml), CDV (94.8%), and CPV (100%). All dogs tested seronegative (0/78; 0%) for influenza A virus. Two 1-year-old dogs stationed in known rabies outbreak areas (Gangwon and Gyeonggi) exhibited VNA titers below the protective level (0.06 and 0.29 IU/ml, respectively). The breed and sex of MWDs were not significantly associated with antibody titers for RABV, CDV, or CPV; however, age was significantly associated with CPV antibody titers, while region of residence was associated with CDV antibody titer. Taken together, the data presented here provide important insights necessary for post-vaccination management and control of infectious diseases in MWDs.