Badgers will be killed in a pilot project to reduce tuberculosis in cattle.
Farmers welcomed a controversial decision by the Welsh Assembly Government to approve a cull in a bovine TB hotspot.
The method and a site with suitable natural or manmade boundaries have not be chosen. Other areas could be considered after the pilot is reviewed.
Officials say bovine TB is out of control in Wales, but conservation groups insist a badger cull will not stop it spreading.
In a statement to AMs in Cardiff Bay, Wales's Rural Affairs Minister Elin Jones said: "This is a difficult decision to take and it has not been taken lightly."
She made clear badgers would remain a protected species and said she had given "due consideration to the divergence of scientific and political opinion".