Her exit from the Knesset comes amid expectation that Prime Minister Benjamin Netanyahu is planning to call early elections, to take place as soon as this September.
Ms Livni told reporters that Israel was too dear to her for her to retire from all politics. She used her resignation speech to warn that Israel was running out of time to resolve its issues. "Israel is on a volcano, the international clock is ticking, and the existence of a Jewish, democratic state is in mortal danger," she said.
"The real danger is a politics that buries its head in the sand."
She also said she had no regrets about her focus on reaching a deal with the Palestinians during her time as Opposition Leader. "Even if the Israeli-Palestinian conflict isn't in vogue right now, there's an urgent need to reach a permanent agreement with the Palestinians as well as with the Arab world."
