Atra-Hasis (Akkadian: 𒀜𒊏𒄩𒋀, romanized: Atra-ḫasīs) is an 18th-century BC Akkadian epic, recorded in various versions on clay tablets and named for one of its protagonists, the priest Atra-Hasis ('exceedingly wise'). The narrative has four focal points: An organisation of allied gods shaping Mesopotamia agriculturally; a political conflict between them, pacified by creating the first human couples; the mass reproduction of these humans; and a great deluge, as has been handed down many times in the different flood myths of mankind. Perhaps the relic of a natural catastrophe in Mesopotamia caused by rising sea level at the end of the last glacial period,^{[better source needed]} the epic links this flood with the intention of the upper gods to eliminate their artificial creatures.

The name "Atra-Hasis" also appears, as a king of Shuruppak on the Euphrates in the times before that flood, on one of the Sumerian King Lists. The oldest known copy of the epic tradition concerning Atrahasis can be dated by colophon (scribal identification) to the reign of Hammurabi’s great-grandson, Ammi-Saduqa (1646–1626 BC). However, various Old Babylonian dialect fragments exist, and the epic continued to be copied into the first millennium BC.

The story of Atrahasis also exists in a later Assyrian dialect version, first rediscovered in the Library of Ashurbanipal, though its translations have been uncertain due to the artifact being in fragmentary condition and containing ambiguous words. Nonetheless, its fragments were first assembled and translated by George Smith as The Chaldean Account of Genesis, the hero of which had his name corrected to Atra-Hasis by Heinrich Zimmern in 1899.

In 1965, Wilfred G. Lambert and Alan Millard published many additional texts belonging to the epic, including an Old Babylonian copy (written c. 1650 BC) which is the most complete recension of the tale to have survived. These new texts greatly increased knowledge of the epic and were the basis for Lambert and Millard’s first English translation of the Atrahasis epic in something approaching entirety. A further fragment was recovered in Ugarit.

The epic of Atra-Hasis contains the myth of the creation of mankind by Enlil, Anu and Enki, also known as Anunnaki and Igigi, the superior and the inferior gods. They seem to have been united in an organization similar to that which existed in Greece between Zeus – as ‘pure spirit or air’ the leading party – and the groups round Poseidon (ocean) and Hades (earth). (Compare also the triple alliance of the party around Zeus and the two from Atlantis to Greece defected groups around Epi- and Prometheus.)

The Eridu Genesis resembles Atrahasis in some central aspects. It reports on the beginning of civilisation on earth, even hinting that the groups of prehistoric man previously roamed Mesopotamia as free nomads.

In the main, the epic reports on a conflict between some of the first Sumerian gods and draws on the earlier myth of the separation of air and earth (‘above’ and ‘below’) in the midst of the cosmic freshwater primordial ocean to clarify their hierarchical relationship. Enlil represents the leading party in the council of gods; the party of Anunnaki around Anu belongs more to the upper heaven, and that of Igigi around Enki more to that below the earth sphere.

All three parties are bound by the Tablet of Destinies, which Enlil is the only one to possess. In the Sumerian myths, its bestowed on him by the earth mother goddess Ninḫursag herself (cf. Anzu myth). His aptitude as the greatest warrior and chief strategist of the divine tribal alliance gives him power over the other parties of gods; only he has the ability to transform present circumstances back into their original state – redefining the course of fate.