15 out of 16 federal states represented in the Bundesrat voted in favour of the treaty, with only Berlin abstaining in a concession by the ruling Social Democrats to their junior Socialist partners, who oppose the treaty.
The lower House, the Bundestag, had already approved the treaty by a majority of 90% last month (EurActiv 25/04/08).
The bill must now be signed by President Horst Köhler to finalise the ratification process, which is considered a mere formality.
Bavarian MP Peter Gauweiler of the Christian Socialist Party (CSU) announced that he would take legal action against ratification of the treaty before the country's highest court today, saying it gives Brussels new competences that are "not compatible with our democratic principles".
With today's vote, 14 national parliaments have approved the Lisbon Treaty. It must be ratified by all 27 member states before it can come into effect.
Ireland is the only country set to hold a referendum on this issue, scheduled for 12 June. Irish Taoiseach Brian Cowen said he considered a 'Yes' vote in the treaty referendum to be in Ireland's "vital national interest".
Public backing of the treaty is not certain, as a large percentage is still undecided, but latest polls have indicated that the balance might tip in favour of the 'Yes' campaign, which has just received a major boost after being backed by one of the three major trade unions.
The other two, however, said they will recommend that their members vote 'No'.