By mid-morning, dozens of rebels boarded five buses that arrived at the police command on the edge of the rebel-held areas ahead of the evacuation, Homs-based activists said. Two of the buses left the city later, heading north.
An activist who goes by the name of Abu Yassin al-Homsi said that up to 1,200 fighters were expected to leave the city Wednesday, handing it over to President Bashar Assad's forces.
The buses were accompanied by Syrian army officers. Homs governor Talal Barazi confirmed that the rebels have started leaving Homs.
In exchange for their evacuation, activists say opposition fighters will allow aid into two northern pro-government villages besieged by the rebels.
The Britain-based Syrian Organisation for Human Rights said that the road to the besieged villages of Nubul and Zahra were opened by the rebels at the same time the evacuation was taking place.
Rebel-held central neighbourhoods of Homs have been besieged by Syrian government forces for more than a year, causing widespread hunger.