Equine herpesvirus 1 (EHV-1) is responsible for several syndromes, such as respiratory disease, abortion, fatal viral pneumonia in neonatal foals, and a neurological syndrome, currently referred to as EHV-1 myeloencephalopathy. The analysis of trace element levels in the sera of EHV-1 infected horses could be useful in clarifying the pathogenesis or pathophysiology of these EHVinduced clinical syndromes. Previous studies have shown significant alterations for some serum trace elements (zinc, iron, copper) in EHV-1 infected horses, and this could be justified by the putative role of these elements in many immunological pathways or by their antiviral activity. The aim of the present study was to perform a comparison by retrospective serological study of 52 EHV-1 infected and non-infected horses, both healthy and ill, to establish whether there were possible alterations in serum levels of arsenic, copper, boron, zinc, iron, chromium, magnesium, manganese, selenium, and silicium. Horses were categorized based on the type of syndrome (respiratory disease, abortion, or neurological disease) and the presence of seroconversion (by virus neutralization) and the result of polymerase chain reaction (PCR) for EHV-1. Levels of serum chromium, copper, selenium, boron, and silicium were significantly different among different groups of EHV-1 infected or non-infected horses. Serum chromium levels were higher in infected horses compared to non-infected individuals (p=0.0001). Levels of serum copper (p=0.001), magnesium (p=0.05), selenium (p=0.004), and silicium (p=0.004) were significantly lower in the horses with neurological disease. While levels of serum chromium (p=0.005) were higher, those of boron (p=0.002) were significantly lower in cases of EHV1 abortion. Overall, the present study revealed alterations in the serum levels of some trace elements between EHV-1 non-infected and infected horses, such as those that aborted or developed neurological signs. However, the relationship between the trace elements and the outcomes of the infection could not be established. Further research is needed to enlighten the effects of trace element alterations on the equine herpesvirus-1 infection pathogenesis in horses.