The collection Fossil Reptiles contains approximately 8,000 fossil specimens of synapsids, ichthyosaurs, Sauropterygia, turtles and lepidosaurs. It includes 600 types and reference items as well as approximately 400 herpetological ichnofossils (trace fossils).

In August 1912, the oldest almost completely preserved turtle Proganochelys was excavated in Halberstadt (Central Germany, Upper Triassic (Jaekel excavation).

Further important items in the collection are:

• basal reptiles from South African Perm (Bradysaurus, Reck Collection)
• Triassic synapsids from Karroo (South Africa)
• Numerous skeletal remains of Nothosaurus from Muschelkalk of Rüdersdorf (east of Berlin)
• Ichthyosaurs and plesiosaurs from the Lower Jurassic of Ohmden and Holzmaden (Southwestern Germany))
• various lepidosaurs such as Sphenodontia and mosasaurs remains from Arkansas

The first fossil footprints were acquired (Chirotherium footprints) from Hessberg near Hildburghausen, Central Germany) around 1835. The turtle footprints from Bedheim (Thuringia, Collection Rühle von Lilienstern) and Iguanodon footprints from the Lowermost Cretaceous around Bückeburg and Hanover should also be mentioned.

Some of the Holzmaden ichthyosaurs are currently undergoing preservation at the Urwelt-Museum Hauff and can therefore not be viewed.