Human rights groups say the media bill infringes freedom of speech
Slovakia's parliament has ratified the Lisbon Treaty, despite a boycott of the vote by some opposition parties.
Previous attempts to hold a vote had to be scrapped because of a series of walkouts by MPs over a media law, which critics say harms press freedom.
But one of the opposition parties decided to drop its boycott and give Prime Minister Robert Fico the majority he needed to push the bill through.
Poland is also close to ratifying the treaty, after a vote by MPs last week.
A final signature is awaited from President Lech Kaczynski, after both houses of parliament backed a law authorising him to ratify the treaty.
Austria's parliament ratified the document on Wednesday.
The treaty, which replaces the failed European Constitution, was signed by European Union leaders in Lisbon in December 2007 and has the aim of making EU institutions more efficient, now that the bloc has 27 member states.
It also creates a new post of president of the European Council.
All 27 member states have to approve the treaty before it comes into force. The Irish Republic is the only country due to hold a referendum.
So far, eight countries have ratified the document - Hungary, Slovenia, Malta, Romania, France, Bulgaria, Austria and now Slovakia.