5 September 2016 Last updated at 18:13 BST
With 500 million consumers, the European market accounts for 73% of the UK's agri-food exports, including 40% of Scottish lamb.
Willie Johnston speaks to Scottish farmers about the prospect of leaving the European Union.
In the last Common Agricultural Policy re-negotiation more than Â£4.5bn was earmarked for Scotland from 2014 to 2020.