Aujeszky’s disease (pseudorabies) is a highly contagious, economically significant disease of pigs. This viral infection causes central nervous system (CNS) signs and high mortality rates in young animals, and respiratory illness in older pigs. Other species may be infected when they come in contact with infected pigs, resulting in a universally fatal CNS disease. Aujeszky’s disease can result in trade restrictions from regions where it is endemic. Eradication programs are underway or have been successful in many countries. In the United States, all states are now considered to be free of the virus in domesticated swine, and a surveillance program is ongoing. The presence of the virus in feral pigs remains a concern.