The agreement, signed by the four nations' prime ministers, calls for a force of up to 3,000 troops to be ready by 2016 for operations such as peacekeeping and crisis management.
The deal was announced at a summit in Warsaw on 6 March that was also attended by German Chancellor Angela Merkel and French President François Hollande.
The four EU countries, known as the Visegrad Four after the castle in Hungary where the first of a long series of regular meetings have taken place since 1991, are all members of NATO.
Merkel said no country alone could cope with its defence needs. “Together we are responsible and we want to take responsibility for the security of Europe ... This cooperation must be strengthened,” she said.
Hollande added that the basis for the deepening of European defence must be a strategic vision, which is to be adopted at the EU summit at the end of the year.
"We must have a common industrial base, jobs and technology to allow the European defence to ensure adequate reliability," Hollande said.
A joint statement said increased multinational defence cooperation is needed because less is being spent on defence during the global financial crisis. It called for NATO and the EU to cooperate closely to develop defence capabilities without duplicating efforts.
Two in one
The Warsaw meeting combined two formats – The Visegrad 4 and the Weimar Triangle, consisting of Poland, France and Germany. It was hosted by Poland, which holds the V4 Presidency.
"This meeting, as well as our cooperation in Brussels, shows that the countries of Central and Eastern Europe together with Germany and France, feel responsible for the unity of Europe and the future of European integration," Polish Prime Minister Donald Tusk said at a joint press conference after the talks.
Tusk also made reference to the EU's current efforts to put in place a reformed Economic and Monetary Union (EMU). "We agree that today’s construction of European unity should be carried out using three tools: Economic and Monetary Union, the competitiveness of European economies and the strengthening of European defense capabilities," he said.
Tusk stressed that the EMU could not divide the EU, but instead be a source of unity. It should therefore be open to all member states of the Union, he insisted. Of the Visegrad 4, only Slovakia is a member of the eurozone.
"The aim of the new architecture of economic and monetary union is to improve the competitiveness of the euro area and non-euro area countries to allow good preparation for the others to join," the Polish prime minister added.
Competitiveness, economic growth, employment and openness are the principles that should underpin the transformation of the economic and monetary union, the participants to the meeting agreed.
"This process should facilitate the integration – every member state that is willing to participate in the closer integration should be accepted with appreciation," says a Polish statement issued after the talks.