The UN said two weeks ago that Syrian President Bashar Assad's government had agreed to let the inspectors, led by Swedish scientist Ake Sellstrom, travel to three sites where chemical weapons were reported to have been used.
UN Secretary-General Ban Ki-moon said the Syrian government had formally agreed to the mission. He added: "The departure of the team is now imminent. The team will remain in the country to conduct its activities, including on-site visits, for a period of up to 14 days, extendable upon mutual consent."
One site to be visited by the UN experts is Khan al Assal in Aleppo, where the Syrian government says rebels used chemical weapons in March. The other two locations have not yet been identified.
Rebels seized Khan al Assal from Assad's forces last month. The opposition Syrian National Coalition has told Mr Ban it would co-operate with the chemical weapons inquiry and welcome UN investigators into all territories under our control.
The UN said it has received 13 reports of possible chemical weapons use - one from Syria's government and the rest mainly from Britain, France and the United States.
The US concluded in June that Assad's forces used chemical weapons against rebel fighters.
President Barack Obama said last year any attempt to deploy or use chemical or biological weapons in Syria would cross a red line.
Syria is one of seven countries that have not joined the 1997 convention banning chemical weapons.