One estimate put the crowd at 70,000
BBC News - Mass protest in Serbian capital to demand early polls
The Serbian capital Belgrade has seen its biggest anti-government protest in years as thousands of disenchanted Serbs demanded early elections.
At least 55,000 people turned out in front of parliament after the opposition Serbian Progressive Party called the rally.
Party leader Tomislav Nikolic gave the government two months to call polls or face a civil disobedience campaign.
Serbia's economic woes have continued as it moves towards EU membership.
It appears that the events in Tunisia and especially Egypt have quite unexpected side effect.
Mass anti-government rally held in Serbia - Yahoo! News
The former allies of the late autocratic leader Slobodan Milosevic want Serbia's government to schedule early elections because of the country's rising poverty and unemployment and falling living standards. They also accuse the government of corruption.
The nationalists are promising economic recovery, higher salaries and new jobs, if they come to power. They have risen in popularity amid Serbia's economic turmoil triggered by the global recession and the slow pace of the country's integration into the European Union the government's main political goal.
"For 10 years, Serbia has lived under a corrupt and incapable government," Serbian Progressive Party leader Tomislav Nikolic told the rally, as the crowd chanted "Thieves! Thieves!" and "Changes! Changes!"
"We will save Serbia when we take over," he said. "No one can stop us."