Equine encephalomyelitis (Eastern and Western) has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of equine encephalomyelitis (Eastern and Western) to be listed, Article 9 for the categorisation of equine encephalomyelitis (Eastern and Western) according to disease prevention and control rules as in Annex IV, and Article 8 on the list of animal species related to equine encephalomyelitis (Eastern and Western). The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, equine encephalomyelitis (Eastern and Western) can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL. The disease would comply with the criteria as in Section 5 of Annex IV of the AHL, for the application of the disease prevention and control rules referred to in point (e) of Article 9(1). The assessment here performed on compliance with the criteria as in Section 4 of Annex IV referred to in point (d) of Article 9(1) is inconclusive. The animal species to be listed for equine encephalomyelitis (Eastern and Western) according to Article 8(3) criteria are several species of mammals, birds, reptiles and amphibians as susceptible species; rodents, lagomorphs and several bird species as reservoirs and at least four mosquito species (family Culicidae) as vectors.