Fossils of Achillobator were first discovered during a Mongolian and Russian field expedition, and collected by Burkhant in 1989, but the specimen was not described and named until 1999, by Mongolian paleontologist Altangerel Perle, and American paleontologists Mark Norell and Jim Clark, although the description was not complete and was actually published without the knowledge of the latter two paleontologists.
Fosilni ostaci Achillobatora prvi su put otkriveni tijekom ruske ekspedicije u Mongoliju 1989. godine, ali nisu bili opisani i imenovani sve do 1999. godine, od strane mongolskog paleontologa Altangerela Perlea i Amerikanaca Marka Norella i Jima Clarka, ali opis nije bio dovršen i u biti je bio objavljen bez znanja zadnja dva autora.