The aurochs (Bos primigenius) was once widespread in Europe, Asia and North Africa. The aurochs was both the ancestor of domestic cattle, and co-existed alongside them for millennia post domestication, before going extinct in 1627. Several studies have suggested that admixture occurred between wild aurochs populations and domestic cattle. To contribute towards our understanding of this process, we generated near complete mitochondrial genomes (between 15063 and 16338 nucleotides) from material derived from the horn of the last aurochs bull (died in 1620) as well as five medieval period Scandinavian drinking horns that have been attributed to aurochs based on their size. Phylogenetic analysis on the data shows that three drinking horns carry European aurochs haplotype P, while two of the drinking horns and the horn of the last aurochs bull carry modern domestic taurine cattle T haplotypes. Our results therefore demonstrate that drinking horns may represent a unique source of material with which to study aurochs genetics, and that the last European aurochs likely underwent a degree of admixture with domestic cattle. We anticipate that future analysis of the nuclear DNA content of such horns will be able to shed further light into the specifics of these admixture events.