Central African Republic Justice Minister Paul Otto and the leader of the opposition Democratic Front, Abdoulaye Miskine, signed the peace accord in the Libyan town of Sert.
Libyan leader Col Muammar Gaddafi and some diplomats were also present.
The opposition leader of the other main rebel movement, Abakar Sabon, is expected to sign this peace accord from his prison cell in the west African country of Benin, where he is currently being held, the BBC's Rana Jawad in Sert says.
This latest peace deal is seen as a significant step for the Central African Republic's national reconciliation process, but it remains to be seen whether it will be implemented on the ground, our correspondent says.
BBC World Service broadcasts to Juba in Southern Sudan and surrounding areas in Arabic on 90.0 FM and in English on 88.2 FM. In Northern Sudan: Khartoum 91.0 FM, Al Ubayyid 91.0 FM, Port Sudan 91.0 FM and Wad Madani 91.5 FM.
“Violence will bring no victory. For the sake of the Darfur civilians, all parties to the conflict have to stop resorting to violence. This is the absolute priority.” - Luis Moreno-Ocampo, Prosecutor of the International Criminal Court, 05 June 2009
"APPREHENSION" by Rob Rooker. Painted on a wall in Maridi, Sudan. The image is of a young Nuer boy looking up among a crowd of people. Click on image for more details. Cards & prints of Rob's paintings can be purchased online at Imagekind.com