A 20-year-old horse was evaluated for symptoms of weight loss, anorexia, fever and lethargy. Clinicalexamination revealed tachypnea, poor body condition and increased breath sounds on auscultation.Ultrasound showed multiple consolidations on the lungs. Thoracic radiography revealed a severe nodularpattern. The horse was treated with antibiotics, corticoids and supportive medication. Since no improvementwas observed, the horse was euthanized.At necropsy, numerous coalescing fibrous nodules were present in the lungs. Histology revealed diffuseinterstitial fibrosis and macrophages containing abundant eosinophilic cytoplasm and oval eosinophilic toamphophilic intranuclear inclusion bodies. Tissue samples tested positive for the presence of equine herpesvirus 5 (EHV 5) on the basis of the polymerase chain reaction (PCR) test. A diagnosis of equine multinodularpulmonary fibrosis (EMPF) was made. This is the first report of EMPF in Belgium. EMPF can be suspectedbased on the ultrasonographic, radiographic and histological changes. EMPF is associated with EHV 5, butthe etiological role of EHV 5 still remains to be proven.