British Prime Minister Tony Blair co-hosts the summit to mark the 10th anniversary of the so-called Euromed process, which aims to boost ties between the European Union and 10 countries stretching from Morocco to Israel.
While another aim of the gathering on Sunday and Monday in the Spanish city where the partnership was launched in 1995 will be to accelerate efforts to set up a free trade area covering both the EU and the Mediterranean, terrorism has moved to the top of the agenda.
British officials said ahead of the summit that Blair would seek pledges from his European and Mediterranean partners to endorse a "code of conduct on countering terrorism", as well as greater cooperation such as in sharing intelligence and managing border movements.
However, the leaders of most Arab states and Israeli Prime Minister Ariel Sharon have chosen not to show up.
Notable absentees in Barcelona will include Jordan's King Abdullah II and Lebanese President Emile Lahoud both of whom are confronting regional turmoil.
Egyptian President Hosni Mubarak, who put forward the idea of a Euro-Mediterranean partnership back in 1991, prior to the actual launching of the process four years later, is also skipping the summit.
Syrian President Bashar al-Assad was not invited amid the controversy of Damascus' alleged involvement in the 14 February killing of former Lebanese prime minister Rafiq al-Hariri.
Mubarak floated the idea of a
Moroccan King Mohamed VI is in Japan, Spanish sources said it was highly unlikely Tunisian President Zine El Abidine ben Ali would attend, and it was unclear if Algerian President Abdelaziz Bouteflika would attend after travelling on Saturday to Paris for medical tests.
Critics say Euromed has achieved little over the last decade, and EU officials admit to shortcomings - saying that is why the process needs to be re-launched.
"Our summit will aim to put the partnership on a sounder and stronger footing, and take courageous decisions to meet the challenges we face as we enter a new phase," European Commission chief Jose Manuel Barroso said ahead of the gathering.
The Euromed partnership - also known as the Barcelona process - joins the 25-nation EU with Algeria, Egypt, Israel, Jordan, Lebanon, Morocco, the Palestinian Authority, Syria, Tunisia and Turkey.
A key goal of the partnership has been to create a Euro-Mediterranean Free Trade Area (EMFTA) to spur economic growth in the region, but analysts are increasingly sceptical of meeting the 2010 target date.
The EU has also poured some 9 billion euros of aid into the region and a similar amount in European Investment Bank loans.