Abstract: Two partial skeletons are described from the Upper Cretaceous Iren Dabasu Formation of Nei Mongol that represent a new therizinosauroid theropod. Neimongosaurus yangi gen. et sp. nov., is the first therizinosauroid to preserve most of the axial column and nearly all of the long bones of a single individual. Distinctive characteristics of the new species include anterior caudal vertebrae with a circular fossa under the transverse process, radius with a prominent biceps tuberosity, proximal pedal phalanges with well developed heels, tibia with an extremely long fibular crest that is much longer than the half length of the tibia, lateral surface of preacetabular process twisted to face dorsally, and caudal vertebrae with widely divergent prezygapophyses. Neimongosaurus displays a few characters that are not reported in other therizinosauroids but do occur in some advanced maniraptorians, such as highly pneumatized vertebra and derived shoulder girdle. Particularly the elongated neck and shortened tail provide further evidence for a close relationship between therizinosauroids and oviraptorsaurs.