None of the euro zone's seven potential future members meet the criteria for accession.
The seven countries have fallen short on both economic and legal requirements, despite considerable progress in recent years, the European Central Bank said today.
Potential members, mostly from the former communist east, have been slow in making progress, with none actually setting a target date for memberships.
This suggests that no new member would join the 19-member currency bloc this decade.
"In none of the seven countries examined is the legal framework fully compatible with all the requirements for the adoption of the euro," the ECB said in its biennial Convergence Report.
"Incompatibilities persist regarding central bank independence," the bank added.
"In addition, in all countries under review, with the exception of Croatia, there are incompatibilities as regards the prohibition of monetary financing."
A wave of former communist countries, including Slovenia, Slovakia, Estonia, Latvia and Lithuania, have joined the bloc over the past seven years. But progress in bigger countries, such as Poland, Hungary and the Czech Republic, has been slow.
Romania, Croatia and Bulgaria are seen as the most advanced towards accession, with all of them discussing a roadmap towards setting a target date.
Among economic criteria, potential members are doing relatively well, with most of them meeting the deficit, inflation and debt criteria.
Athough Sweden is also reviewed regularly by the ECB, the country is not even discussing accession, with domestic opinion polls showing that two thirds of voters oppose membership.