The EU "crisis management concept" is the first step towards sending a force.
Fighting between Muslims and Christians in CAR has driven nearly a million people from their homes.
Currently about 4,000 African troops and 1,600 French troops are trying to prevent more bloodshed in CAR. The cost of an EU mission is not yet clear.
Correspondents say an EU force of up to 1,000 troops is likely.
A European diplomat close to the talks said the EU foreign ministers in Brussels had made "a commitment to kick off operational planning".
This week the EU will seek a mandate at the United Nations for such an operation, and EU experts will go to the CAR capital Bangui to assess the cost, the diplomat told the BBC.
At the moment "it is unclear what exactly will be needed", the diplomat explained, requesting anonymity.
Greece has offered to host a mission headquarters and Estonia is prepared to send up to 55 troops, the diplomat said.
Several other countries are considering troop contributions, including Lithuania, Romania, Austria and Finland.
The EU operation would provide "temporary support, for a period of up to six months, to establish a secure environment in the Bangui region, with a view to handing over to the African Union (AU)", the ministers said in an official statement after their Brussels talks.
The plan is to turn the current AU deployment in CAR into a UN peacekeeping operation, the statement said.
The aim is also to stabilise the situation so that urgently needed humanitarian aid can reach the many suffering civilians.
EU foreign ministers have agreed on a blueprint for sending hundreds of European troops to the Central African Republic to help quell violence there.