Israeli Prime Minister Ehud Olmert has submitted his resignation letter to the country’s President, Shimon Peres.
Mr Olmert may remain as interim prime minister for several weeks while his successor as leader of the Kadima Party tries to form a new government.
He is to be replaced by Israel’s Foreign Minister Tzipi Livni, who has six weeks to gather a fresh coalition.
Mr Olmert announced he would step down in July after facing growing pressure over multiple corruption inquiries.
The BBC’s Wyre Davies in Jerusalem says that forming a coalition will not be an easy task as Kadima does not have a majority in the Israeli parliament, known as the Knesset.
The same parties, particularly religious parties from the right, who joined the Olmert government will not necessarily support Ms Livni, the correspondent says.
It is a complicated process that may end in general elections at the start of next year, until when Ehud Olmert may remain as prime minister, the correspondent adds.