During the past years, renewed interest in the presence of viable prokaryotes in ancient salt deposits has surfaced, which was partly stimulated by the detection of halite on Mars and elsewhere in the universe The first cultivations of halophilic micro-organisms from Permian salt deposits (about 250 million years old) were reported in the 1960s and met with considerable skepticism. Some 30 years later, successful isolations of halophilic bacteria and archaea (haloarchaea) from ancient evaporites, including detailed taxonomic descriptions, began to be published No methods are available yet which would be sensitive enough to ascertain the age of a single prokaryotic cell. The age of the salt sediments, which can be estimated by radioactive dating, stratigraphy, and pollen analysis and references therein), is therefore deemed the presumed age of the micro-organisms found inside. This perception has raised many discussions, mainly on the possibility of microbial contamination during isolation and processing of samples, as well as uncertainty about their real age Retrieval of DNA from ancient sediments repeated isolations from the same site and recent reports of successful haloarchaeal cultivations from well-dated bore cores supported the presence of biological material in evaporites of great geological age. Survival of cells over millenia of years in dry sediments or sedimentary rocks on Earth would have important implications for the search for life on other planets, where sediment-like structures exist