Syrian Deputy Foreign Minister Faisal al-Maqdad and Arab League Assistant Secretary General Ahmed Ben Helli inked an Arab observer mission to monitor a deal to end the Syrian crisis at League headquarters in Cairo, an AFP reporter said.
Speaking at a news conference in Damascus, Foreign Minister Walid Muallem said the government had agreed to the protocol "because we want a political solution in Syria, and because we want to find a solution with Arab League help."
"Signing the protocol is the start of cooperation with the Arab League and we will welcome the observers' mission from the Arab League," he said.
"Sovereignty is protected in the text of the protocol," he added.
"Article 8 of the Arab League charter protects existing structures and bans countries from interfering... In this protocol we are talking about protecting civilians from terrorist groups."
Syria has consistently rejected the view of Western governments and human rights groups that the protests in the country have been overwhelmingly peaceful, insisting that they are the work of "armed groups".
The 22-member Arab bloc had been trying to persuade Damascus to accept the observer mission for weeks.
Under the terms of the deal that the observers are intended to oversee, Syrian security forces are required to pull back from the towns and villages that have been at the centre of nine straight months of protests and open negotiations with the opposition under League auspices.
On November 27, the bloc approved a raft of sanctions against Syria for failing to heed an ultimatum to admit the observers, including suspension from its meetings.
Earlier this month, Syria finally said it would allow in the mission, but laid down a number of conditions, including the lifting of sanctions.
The United Nations says at least 5,000 people have been killed since March.