king of Babylonia 721–710 and for nine months in 703, who maintained Babylonian independence in the face of Assyrian military supremacy for more than a decade.

Commencing in 728 the king of Assyria also officially held the title of king of Babylonia. During that time Merodach-Baladan, a member of the Yakin tribe, was a district ruler in Chaldea. During the unrest surrounding the accession of Sargon II of Assyria in 722, Merodach-Baladan entered Babylon and claimed the Babylonian throne, which had belonged to his forebear Eriba-Marduk. An attack by the Elamites two years later so weakened the Assyrians—though both sides claimed victory—that, as king of Babylonia, Merodach-Baladan remained unmolested by Assyria for the next 10 years.

Sargon's inscriptions portray Merodach-Baladan as a usurper who oppressed Babylonia and relied on Elamite military power. On the other hand, Merodach-Baladan claimed to be the legitimate heir who had driven the Assyrians from Babylonia. Contemporary Babylonian documents indicate that temples were repaired, irrigation projects were carried out, and life was normal during his reign.

According to Assyrian accounts, Sargon marched south against Babylonia in 710. After defeating the Elamites and Merodach-Baladan's other allies, he turned toward Babylon. Merodach-Baladan fled, and the leading citizens of Babylon brought Sargon unopposed into the city, where he officially became king of Babylonia. The next year Sargon captured and destroyed Merodach-Baladan's capital, Dur-Yakin. Sometime after the death (705) of Sargon, Merodach-Baladan sent an embassy to Hezekiah of Judah in an attempt to foment unrest against the new Assyrian monarch, Sennacherib. In 703 he again seized the Babylonian throne. Before the end of the year, however, Sennacherib marched south and defeated the Babylonian forces. In 700 Sennacherib marched to Bit-Yakin in pursuit of Merodach-Baladan, who again fled, this time to southern Elam, where he died sometime before 694.