The withdrawal will restore state control over the eastern Qalamoun enclave, some 40 km (25 miles) from Damascus.
Assad, backed by Russia and Iran, is seeking to wipe out the last few rebel enclaves near Damascus, building on momentum from the defeat of the insurgency in eastern Ghouta, which was the last major opposition stronghold near the capital.
State TV said rebel fighters and their families would be transported from eastern Qalamoun to Idlib and Jarablus, a rebel-held territory at the border with Turkey, with 3,200 militants and their families expected to leave on Saturday.
The spokesman for one of the rebel groups in eastern Qalamoun said the insurgents had agreed to the deal after intensified Russian shelling killed six people in areas near the town of al-Ruhaiba earlier this week.