Opposition activists are later expected to march to the parliament building
More than 50,000 opposition supporters in Georgia have gathered on independence day to demand President Mikhail Saakashvili's resignation.
The crowd sang the national anthem and heard speeches by opposition leaders in a stadium in the capital, Tbilisi.
The opposition has been holding daily rallies since April. Critics accuse Mr Saakashvili of bungling last year's war with Russia and restricting democracy.
Earlier, the government called off a major military parade to avoid clashes.
The parade was due to travel along the capital's main street, Rustaveli Avenue, which opposition activists have blocked for weeks with mock prison cells.
The BBC's Tom Esslemont in Tbilisi says independence day is traditionally when Georgians get together to unite behind the country.
This year, the thousands who gathered at Dynamo Tbilisi's 60,000-seat stadium are united not just behind Georgia but also in their support for the opposition parties, our correspondent says.
To huge cheers from the crowd, who waved red and white handkerchiefs and flags, the opposition leaders walked into the stadium and repeated their demand that Mr Saakashvili step down immediately.
"I'm sure we will win. We will not take a single step back. All we demand is the president's resignation," said Nino Burjanadze, a former ally of Mr Saakashvili who now leads the Democratic Movement-United Georgia party.
The opposition supporters are later expected to march to the parliament building, which has been the main location of their protests in the past six weeks.
Mikhail Saakashvili's opponents say he mishandled last year's war with Russia
Our correspondent says that although the numbers turning out at daily rallies have been dwindling, perhaps the biggest coup for the opposition so far is that it has forced the government to cancel the annual military parade.
The fact that it is a national holiday and an important occasion in Georgia may account for the large turnout at the Dynamo stadium, but no matter how much support they say they have, the opposition leaders say they will continue their demonstrations until President Saakashvili resigns, he adds.
In a joint statement on Monday, the US and EU urged the government and opposition to "end the current stalemate on the streets and begin negotiations immediately and without preconditions on a new programme of reforms to invigorate Georgia's democracy".
But, our correspondent says, with Mr Saakashvili insisting that he will not resign, it is unclear how and when these protests will end.