Blood samples were collected from wild boar (Sus scrofa) shot during the hunting season from 1999 to 2005 in the Czech Republic. Sera were tested by enzyme-linked immunosorbent assay for the presence of antibodies against classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), Aujeszky's disease virus (ADV), and bovine viral diarrhea virus (BVDV). Indirect fluorescence antibody test was used for detection of antibodies against porcine circovirus type 2 (PCV-2) and transmissible gastroenteritis virus (TGEV). Antibodies against ADV, BVDV, PCV-2, and TGEV were detected in 30% (101 of 338), 1% (2 of 352), 43% (57 of 134), and 1% (1 of 134) of wild boars, respectively. Sera of 6,471 and 362 tested wild boars were negative for the presence of antibodies against CSFV and SVDV, respectively. This is the first survey of TGEV antibodies in wild boars and the first serologic survey of viral diseases in wild boars in the Czech Republic. Wild boars in the Czech Republic may act as a potential reservoir of ADV and thus have a role in the epidemiology of this disease.