The deal was signed in the presence of UN Secretary General Ban Ki-moon in the Ethiopian capital, Addis Ababa.
He said he hoped it would bring "an era of peace and stability" to the region.
As many as 800,000 people have been displaced since the March 23 rebel group took up arms against the Kinshasa government last May.
"It is only the beginning of a comprehensive approach that will require sustained engagement," Mr Ban said.
The agreement, signed by leaders and representatives of 11 countries of the Great Lakes region, may lead to the establishment of a special UN intervention brigade in eastern DR Congo, along with political efforts to bring peace.
An initial attempt to get the peace agreement signed last month was called off at the last minute.
Mineral riches Leaders from Mozambique, Rwanda, Tanzania, South Africa, Democratic Republic of Congo, Congo Republic and South Sudan attended the signing.
DR Congo deal 'a significant event' The M23 rebels say they want to improve living conditions for the people of eastern DR Congo, but the UN says they are supported by Rwanda, which has been heavily involved in its eastern neighbour since those responsible for the country's genocide fled there en masse in 1994.
Bosco Ntaganda, who is accused of being one of the M23 leaders, was an officer in the Rwandan army before he left to join a rebel movement in DR Congo. The ICC accuses him of using child soldiers and the UN says he controls several mines in the east of the country.
The group briefly seized control of the city of Goma last November after carving out an area for themselves in North Kivu province.
DR Congo's government and rebels have been holding talks in Uganda aimed at reaching an agreement on a range of issues. In January, the rebels declared a unilateral ceasefire.
An earlier attempt to reach a deal collapsed in December after the group accused President Joseph Kabila of failing to honour a deal to integrate rebels into the army.
The region's mineral riches have been plundered by numerous groups and countries over the past 15 years and little has been spent on DR Congo's infrastructure.