Karl Eduard von Eichwald was a Baltic German geologist, physician, and naturalist, who worked in Russia.

Eichwald was a Baltic German born at Mitau in Courland Governorate.

He became doctor of medicine and professor of zoology in Kazan in 1823; four years later professor of zoology and comparative anatomy at Vilnius;

in 1838 professor of zoology, mineralogy and medicine at St. Petersburg; and finally professor of palaeontology in the institute of mines in that city.

He travelled much in the Russian empire, and was a keen observer of its natural history and geology. He died at St. Petersburg.

His published works include

• Reise auf dem Caspischen Meere und in den Caucasus, 2 vols. (Stuttgart and Tübingen, 1834-1838);
• Die Urwelt Russlands (St Petersburg, 1840-1845);
• Le Lethaea Rossica, ou Paléontologie de la Russie, 3 vols. (Stuttgart, 1852-1868), with Atlases.

In the scientific field of herpetology he described several new species of reptiles.

His work is not devoid of serious shortcomings, dependent in part on the nature of the compiler. In old age, few self-confident scientists are willing to admit their mistakes. Part of the errors were because of low-quality material, which had been gathered for him by often inexperienced or illiterate people. Therefore, the conclusions are not always trustworthy.