The work analyses changes in agri-food trade flows of the Vissegrad Four Countries (V-4), i.e. Czech and Slovak Republics, Hungary, Poland, caused by the future enlargement of the EU Customs Union. The enlargement will result in the removal of trade barriers between old members and new members of the European Union but the latter shall adopt the EU's Common External Tariff. In 1998, about 78% of V-4 agri-food imports were carried out under preferential regimes. The adoption by V-4 of the Common External Tariff will reduce by 4% the tariff protection against agri-food imports from third countries, as compared to 1998. However, changes in this protection will vary due to the heterogeneity of V-4 trade policies. In the Slovak Republic, European integration will lead to an increased level of protection for cereals, fruits, vegetables and dairy products, i.e. sectors that are currently very liberalized.