Wild boar is closely related to domestic pigs in terms of genetic homogeneity and the possibility of a source of infection by contact. This study investigated the prevalence of viral diseases from wild boars inhabiting Gyeongsangnam-do, South Korea. A total of 374 blood samples were collected and subjected to antigen tests to detect African swine fever virus (ASFV), Porcine circovirus type-2 (PCV2), Porcine reproductive and respiratory syndrome virus (PRRSV). For seroprevalence, PCV2, PRRS, classical swine fever virus (CSFV), Aujezsky’s disease (ADV), and foot and mouth disease virus (FMDV) were investigated. The antigenic analysis revealed 73 positive cases (19.5%) for PCV2, while no positive cases for ASFV and PRRSV. For the antibody test, 225 (60.2%), 2 (0.5%), and 48 (12.8%) cases were detected against PCV2, PRRSV, and CSFV, respectively. There were no antibodies detected against both ADV and FMDV. Our results suggest that the viruses infecting both wild boar and domestic pig, mainly PCV2, are circulating in the wild boar population thus, the consistent monitoring of prevalence in wild boar will be needed for transboundary spillover to the domestic pig.