Sweden has become the 25th EU member state to approve the Lisbon Treaty.
The treaty was approved by the Swedish Parliament, the Riksdag, yesterday evening.
According to the Swedish Parliament's rules of procedure, adoption of the bill requires a two-thirds majority in the chamber. The bill was adopted by 243 votes in favour, 39 against and 13 abstentions.
José Manuel Barroso, president of the European Commission, described Sweden's move as "an important step forward."
"The Treaty of Lisbon will make the Union more democratic, transparent and stronger on the world stage. It would certainly have helped during the Georgia and financial crisis.
"We now await the approach that the Irish Government intends to take at the December European Council so that we can move forward with the ratification process," he said.
Last week, Minister for Foreign Affairs Micheál Martin said the Government will make a decision on whether to hold a second Lisbon Treaty referendum before a meeting of EU ministers next month.