Top Obama administration officials have been reluctant to visit Iraq since the March election failed to produce a clear winner. Biden's trip may signal the U.S. is stepping up its efforts to hammer out an agreement among Iraqi political rivals and get a new government in place as soon as possible.
The vice president was upbeat upon arrival.
"I remain, as I have been from the beginning, extremely optimistic about the government being formed here," Biden told reporters.
Biden is the White House's point man on Iraq issues, and was last in Iraq in January. He visited three times last year.
He will meet with Iraqi President Jalal Talabani, Prime Minister Nouri al-Maliki and the premier's main political rival, Ayad Allawi and "affirm the United States' long term commitment to Iraq and discuss recent developments," the White House said in a statement Saturday.
An aid to al-Maliki told The Associated Press that the Iraqi prime Minster will meet with Biden on Sunday to discuss the U.S. withdrawal, ways to deepen ties between the two countries and the formation of the new government.
"The aim of Biden's visit is not to impose a point of view nor an attempt to interfere in Iraq's political process," Yassin Majid said.
Iraq's newly elected parliament is scheduled to meet later this month for the second time since the March 7 vote.
Parliament has only about a month to end the impasse before the start of Ramadan in August, when little official business gets done in the Arab world. Adding to the urgency, all but 50,000 U.S. troops are set to leave Iraq by the end of August in a test of whether the fledgling democracy's security forces are ready to protect its people from insurgents and other terror threats.
Persistent violence has raised fears that al Qaeda in Iraq and other militants are trying to exploit the political deadlock to foment unrest and derail security gains as the American military prepares to withdraw all of its troops by the end of next year.
Analysts and some Iraqi lawmakers have warned that the end to the political gridlock could still be months away.
But Michael O'Hanlon, an Iraq expert at the Brookings Institution, a Washington D.C.-based think tank, said Biden can perhaps speed things up by "carefully but clearly reminding Iraqi politicians that the future relationship with the U.S. is not yet guaranteed to be close."
Some Iraqi political leaders, including Foreign Minister Hoshyar Zebari, who greeted the vice president at the airport, have previously accused the U.S. of being more focused on the withdrawal of American troops than on helping Iraq end its political impasse. There are currently about 77,500 U.S. troops on the ground in Iraq.
Al-Maliki, who leads a Shiite political coalition, is battling to keep his job after the Sunni-backed Iraqiya list narrowly won the most seats in the March 7 vote. But al-Maliki has tried to outmaneuver his challengers by creating a so-called super-Shiite alliance that would give him more seats in parliament than Iraqiya, which is led by his chief rival, Allawi.
Iraqiya leaders have claimed they should have the first crack at forming the government because they won the most seats on election day. But a March court opinion opened the door to the possibility that the largest bloc could be one created after the election through negotiations - meaning that if the super-Shiite coalition holds together, it could have the right to form the government.
The vice president landed at an air force base in Baghdad on Saturday afternoon and headed into meetings with U.S. Ambassador to Iraq Christopher Hill, the top American military commander in Iraq, U.S. Army Gen. Ray Odierno, and the top UN envoy to Iraq, Ad Melkert.
High ranking U.S. senators - Republicans John McCain from Arizona and Lindsey Graham from South Carolina, as well as Joe Lieberman, an independent from Connecticut - also met Biden at the Baghdad airport on Saturday. They are in Iraq on an unrelated trip and did not travel here with the vice president.
Earlier on Saturday, McCain, the top Republican on the Senate Armed Services Committee, met with Prime Minister Nouri al-Maliki in the Iraqi capital.