Many Palaeolithic archaeological sites have been excavated in the Cantabrian region of northern Spain, between the Cantabrian mountain range and the coast of the Bay of Biscay. The analyses of the materials thus recovered in sites such as El Castillo, Morín, Pendo, Covalejos, Esquilleu, El Mirón, Hornos de la Peña, El Cuco, El Ruso, Lezetxiki, Axlor, Arrillor, Amalda, Abauntz, and Gatzarria, among others, have contributed greatly to the understanding of Neanderthal animal-based subsistence in the area. However, most of the sites studied are in the eastern part of this area, and we know little on the western part, from just a handful of sites (El Sidrón, Llonín, La Viña, and La Güelga in Asturias; Cova Eirós in Galicia) and the zooarchaeological information has been limited, but is currently growing. El Sidrón has many cannibalized Neanderthal bones but few faunal remains, the Llonín cave shows short Neanderthal occupations, the Mousterian of La Viña yielded few faunal remains, and the three Mousterian levels of Cova Eirós were also short occupations. In this work, we present the zooarchaeological and taphonomical analyses from the Mousterian Level XV of Sopeña (Onís, Asturias), very rich in faunal remains, aiming to shed light on the Neanderthal subsistence on the western part of northern Spain. Faunal remains from Sopeña Level XV appear very modified by neanderthal actions. They did exploit a variety of ungulates from diverse ecosystems, both high mountains and river valleys, displaying the great versatility and adaptability in their subsistence strategies.