Herpesviruses infect a wide variety of animals from mollusks to mammals. Herpesviruses belong to the most complex and most widespread viruses. Herpesvirus replication is a complex process. The spread of herpesvirus infections occurs not only via free virions but also by direct cell‐to‐cell spread. The incubation period in pigs is affected by the infectious dose, the route of infection, and the host species. Infection of pigs with pseudorabies virus (PRV) produces a high fever, followed by anorexia, listlessness, dyspnea, excessive salivation, vomiting, trembling, and, eventually, marked incoordination, especially of the hind legs. Gross lesions may occur in non‐neural tissues, including lymphoid organs, and respiratory, digestive, and reproductive tracts. Microscopic lesions in pigs reflect the neuroinvasive and epitheliotropic properties of PRV. Porcine cytomegalovirus is ubiquitous in pig populations and induces latent infections in pigs. Malignant catarrhal fever is a sporadic, systemic gammaherpesvirus infection of ungulates.