Portugal's parliament have approved the European Union reform treaty which was signed by the 27-nation bloc in Lisbon during the country's EU presidency last year.
The treaty still needs to be ratified by Portugal's President Anibal Cavaco Silva.
"I would like to congratulate Portugal on the successful approval of the Treaty of Lisbon by the parliament today," the President of the European Commission, Jose Manuel Barroso, said in a statement.
"This is another important step towards our objective of a new treaty in force by January 1 2009."
The treaty, which includes a long-term president for the European Council and a foreign policy chief with greater powers, has to be approved by all EU member states to take effect.
It has been ratified or approved by parliaments in eight EU countries. Ireland is the only state in the EU planning a referendum on the treaty, in June.