The Campylobacterales are an order of Campylobacterota which make up the epsilon subdivision, together with the small family Nautiliaceae.

[1] Comparative genomic analysis has led to the identification of 49 proteins which are uniquely found in virtually all species of the order Campylobacterales.

Additionally, two conserved signature indels have been identified which, along with the proteins, serve as molecular markers for the order.

The indels are a three-amino-acid insertion in the B protein of the Uvr ABC system, and a two-amino-acid deletion in phenylalanyl-tRNA synthetase.

[2] The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[3] and National Center for Biotechnology Information (NCBI)[4] Nitratiruptor Nitrosophilus Hydrogenimonas Thioreductor Wolinella Helicobacter [incl.