The aim of this study is to determine the frequency of the equine herpes virus 2 (EHV-2) in chronic respiratory diseases. A broncho-alveolar lavage was performed under endoscopy in 30 animals (27 horses, 2 donkeys and 1 mule) with respiratory signs and then the respiratory fluid was analyzed by PCR. The EHV-2 was isolated in 10 horses (prevalence: 33.3%) in association with the EHV-4 in 2 cases. The EHV-2 frequency was higher in males (47.4%) than in females (9.1%) and in young horses (> 5 year old) (43.8%) than in older ones (21.4%). These results confirm the EHV-2 involvement in chronic respiratory diseases especially in the young population.