Attending the conference were representatives from Croatia, Slovenia, Italy, Bosnia and Herzegovina, Serbia and Montenegro, and Albania.
The Adriatic Euroregion will be formally launched after the six states' regional representative bodies adopt the Euroregion's statute and the founding assembly will be held at Brijuni, Croatia, in July.
Ivan Jakovcic, head of the northern Croatian Adriatic County of Istria, was elected president of the Euroregion, which will be based in Pula, Croatia, but will also have an office in Brussels.
Speaking of the significance of the declaration, Council of Europe Secretary-General Terry Davis said the Adriatic was rich in terms of history, culture, and natural resources, but had been burdened with wars throughout history. He added this was why it was necessary to draw lessons from that and build a better and safer future, notably through interregional cooperation.
This region is not the European Union's waiting room nor its alternative but represents the richness of interregional cooperation in the 21st century, said Davis.
Speaking to the press, Jakovcic underlined that without the Adriatic's east coast there was no real or integral Europe.
"Now Europe does not end on the Slovene border but begins there. I am certain the Adriatic Euroregion is one of the best mechanisms of Europe's modern political architecture which can offer a strong integration of regions on the Adriatic in this part of Europe and thus help states complete the European integration process more easily," said Jakovcic.
He declined to say why representatives of Lika-Senj and Sibenik-Knin counties were not in attendance but said that Prime Minister Ivo Sanader and Foreign Affairs and European Integration Minister Kolinda Grabar-Kitarovic had strongly supported the launching of the Euroregion.
Slovenia did not sign the declaration because authorised representatives of its maritime municipalities did not attend the conference.
The Adriatic Euroregion's objectives include preservation of the stability of its regions, strengthening of social and economic cohesion, sustainable development, the advancement of agriculture, fisheries and tourism, and environmental protection.
The Adriatic Euroregion will unite seven Italian regions, three Slovene maritime municipalities, seven Croatian counties, Bosnia's Herzegovina-Neretva Canton, Montenegro, and seven Albanian provinces.