The Aitym Formation is a geological formation in Uzbekistan which possibly dates to the Santonian stage of the Late Cretaceous period.

However, certain fossils suggest the formation was deposited during the Santonian stage of the Late Cretaceous period.

[1] A diverse fauna has been unearthed from the Aitym Formation including oysters, ammonites and many marine vertebrates, including an abundant assemblage of chondrichthyans (cartilaginous fish), a rarer assemblage of osteichthyans (bony fish), and rather infrequent finds of plesiosaurs, and sea turtles.

Terrestrial vertebrate remains are extremely rare in the formation.

A few bones of salamanders, lizards, crocodiles, possibly terrestrial turtle remains, dinosaurs (including birds), and mammals have been found in the formation.