"The vice president has arrived in Iraq for meetings with (the) Iraqi leadership focused on encouraging Iraqi national unity and continued momentum in the fight against ISIL," a statement from Biden's office said, using an acronym for the Islamic State jihadist group.
"The vice president will also be discussing steps the international community can take to promote Iraq's economic stability and further regional cooperation," the statement said.
It is the highest-ranking visit by a US official to Iraq since Biden went there in 2011.
"The vice president has been the point person on Iraq for the administration since the beginning," a US official told reporters on Biden's plane.
"He's been itching to get back for a while -- looking for an opportunity. This seemed like a good moment to do it," the official said.