Equine herpesvirus type 1 (EHV-1) is a double -stranded DNA virus occurring in all breeds of horses. It belongs to the Varicellovirus genus, Herpesviridae family and Alphaherpesvirinae subfamily. EHV-1 may cause epidemic respiratory disorders, abortions in pregnant mares, neonatal foal death, chorioretinopathy and also neurological disease, termed equine herpesvirus myeloencephalopathy (EHM). The infection spreads by inhalation of the aerosolised infectious virus or close contact with aborted fetuses, fetal membranes and fomites. Lifelong latency has been demonstrated especially in trigeminal ganglion, lymphatic tissues draining the respiratory tract and in peripheral blood leukocytes, from where the virus can be periodically reactivated. Both traditional serologic and virus isolation tests have been available for a long time, however, these assays have disadvantages, interfering with fast and reliable detection of EHV-1. Advances in molecular biology and the use of quantitative PCR system allow for more sensitive detection in a single genome copy range, higher analytical specificity and calculation of EHV-1 viral loads.