Utnapishtim, whose name means "he found life" or "he who saw life", is also known as Atrahasis, meaning "the exceptional wise one". In the Akkadian sources, a wise citizen of Shurrupak on the banks of the Euphrates, or Ziusudra in the Sumerian poems. A wise king and priest of Shurrupak, he appears in the Epic of Gilgamesh as one of the two human survivors, who along with his wife and with 'the seed of all living creatures' survived a great flood sent by Enlil to kill everything on Earth. The Flood episode occurs in the eleventh table of the Gilgamesh epic. Utnapishtim was secretly warned by the water god Ea of Enlil's plan, and constructed a boat to save himself and representatives of each species of animal.

When the flood waters subsided, the boat was grounded on the mountain of Nisir . When Utnapishtim's ark had been becalmed for seven days, he released a dove, who found no resting place and returned. A swallow was then released who found no perch, but the raven which was released third did not return. Utnapishtim made a sacrifice and poured out a libation on the top of mount Nisir.

Utnapishtim and his wife were granted immortality after the flood. Afterwards he is taken by the gods to live for ever at 'the mouth of the rivers' and given the epithet 'Faraway.' Later Gilgamesh decided to find Utnapishtim who still lived in the land of Dilmun, in the garden of the sun, in his fruitless search for eternal life.

The literary version we have from the library of Assurbanipal dates from the 7th century, but translations of Sumerian texts have carried the history of the epic back into the third millennium B.C. There are many similarities between Utnapishtim and the more recent legend of the biblical Noah. Scholars usually assume that the author of this part of the Bible has had knowledge of the Epic of Gilgamesh.