Italy's Parliament ratified Accession Protocols of Bulgaria and the other six countries - Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovenia and Slovakia -invited to join NATO.
Some 370 Italian MPs backed the sixth countries, other 17 MPs voted against, while another 2 withheld from voting.
Thus Italy became the seventh country to ratify those protocols following the yes-votes of Hungary, Canada, Norway, the United States and Denmark. The approval of all the 19 allies is needed.
The new NATO members will increase the allied forces by about 200,000 troops and will add new bases.
The seven countries were invited to join NATO at the Alliance's summit in Prague.