Deinococcus radiodurans

Deinococcus radiodurans is a bacterium, an extremophile and one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid, and therefore is known as a polyextremophile. The Guinness Book Of World Records listed it in January 1998 as the world's most radiation-resistant bacterium or lifeform.

Several bacteria of comparable radioresistance are known, including some species of the genus Chroococcidiopsis (phylum cyanobacteria) and some species of Rubrobacter (phylum Actinomycetota); among the archaea, the species Thermococcus gammatolerans shows comparable radioresistance.