| Named By: | A. N. Riabinin in 1930 |
| Time Period: | Late Cretaceous, 66 Ma |
| Location: | North East China (Manchuria) |
| Size: | Unavailable |
| Diet: | Herbivore |
| Fossil(s): | Partial remains |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischia | Ornithopoda | Hadrosauroidea | |
| Also known as: | | Trachodon amurensis | |
Mandschurosaurus is a genus of hadrosaurs based on material from the Upper Cretaceous of Belye Kruchi, Manchuria. M. amurensis is based on a poorly preserved and incomplete skeleton collected by Russian scientists in 1914 from the banks of the Amur River. It was the first dinosaur genus named from China, and a mounted skeleton is on display at the Central Geological and Prospecting Museum in St. Petersburg. However, much of the skeleton is plaster. Regardless, the remains represent a large hadrosaurid. There has been some debate regarding the validity of this genus. Brett-Surman (1979) first considered it a nomen dubium, though some later workers have continued to see it as a valid taxon (Chapman et Brett Surman, 1990, for example). Most recently, Horner et al. (2004) listed the type species as a nomen dubium. The holotype material was initially referred to the genus "Trachodon" (also a nomen dubium), but later reassigned to a new genus by Riabinin (1930).
Over the years, three species have been placed within this genus: Mandschurosaurus amurensis, M. mongoliensis, and M. laosensis. Brett-Surman (1979) considered M. mongoliensis a distinct genus, which he named Gilmoreosaurus. Horner et al. (2004) considered M. laosensis a nomen dubium. This leaves only Riabinin's original species, M. amurensis, as a possibly valid taxon.