An in situ hybridization (ISH) and in situ polymerase chain reaction (in situ PCR) tests with a digoxigenin (DIG)-labeled DNA probe were used to detect the latency of pseudorabies virus (PRV) DNA in formalin-fixed, paraffin-embedded pig tissues. Tissues were collected 3 months following inoculation with the PT strain of PRV. To confirm the specificity of ISH and in situ PCR. PCR was used to amplify the IE and gE genes of the PRV PT strain. In situ methods are more rapid and accurate for the diagnosis of latent PRV infections. The sensitivity of these two techniques was compared. The in situ PCR test was found to be more sensitive than ISH and allowed the rapid, sensitive, and specific detection of latent PRV infections.