Chondrostoma (from the Ancient Greek roots χόνδρος (khondros) 'lump' + στόμα (stoma) 'mouth' = 'lump-mouth') is a genus of ray-finned fish in the family Leuciscidae. They are commonly known as nases, although this term is also used locally to denote particular species, most frequently the common nase (C. nasus). The common name refers to the protruding upper jaw of these fishes; it is derived from the German term Nase 'nose'.

Several species have a very restricted range. Some of these endemics are very rare nowadays, and at least one species is globally extinct.

In 2007 it was determined that the presumed monophyletic group consisted of six at least partly independent lineages of Leuciscinae, meaning that the rasping feeding apparatus evolved more than once. It was proposed to split the genus in six in consequence: Achondrostoma, Chondrostoma, Iberochondrostoma, Pseudochondrostoma, Protochondrostoma and Parachondrostoma. But at least Achondrostoma and Iberochondrostoma may not be separable.

These are the currently recognized species in this genus: