A seven-year-old horse was euthanised after exhibiting a severe and rapidly progressive neurological disorder. Tissue samples were despatched to the Italian Reference Centre for Animal Foreign Diseases (Istituto 'G. Caporale' in Teramo) for diagnosis. All laboratory tests for equine neurotropic viruses gave negative results. Scattered perivascular inflammatory infiltrates and several parasites that were morphologically classified as Halicephalobus gingivalis, were seen within the brain upon microscopic examination. Pathological findings led to the diagnosis of parasitic meningo-encephalitis caused by H. gingivalis. This case report confirms that halicephalobosis should be taken into account in the differential diagnosis of equine encephalopathy and it also highlights the value of a multidisciplinary approach to problem solving in veterinary medicine.