Thousands of protesters gathered in Prague to call for the Czech Prime Minister to resign.
The demonstrations marked the largest anti-government protest in Prague since the 1989 pro-democratic Velvet Revolution.
Protesters came to the capital from all corners of the Czech Republic to attend Sunday's demonstration, the most massive of recent street protests opposing Andrej Babis.
The demonstrators see the leader as a threat to democracy and have expressed concern over the independence of the country's legal system.
The protesters also are demanding the resignation of Babis' new justice minister and say the minister might compromise the legal system, as prosecutors consider whether to indict MR Babis on fraud charges involving European Union funds.
Mr Babis denies wrongdoing and says there is no reason for him to resign.
Organisers said they believed that around 250,000 people had attended Sunday's rally, from all around the country.
However, this figure could not be verified.
Banners saying "Resign", "We've had enough" were held and some waved Czech or EU flags.
Filip Rubas, who joined protests in 1989 against the then communist regime, said he attended t on Sunday to send a message to politicians that they will be held accountable.
"We think that our leaders need to be reminded very strongly that they do not own our country, that they are not above the law (or constitution) and that there are still enough caring people who are not brainwashed by hateful propaganda," he said.
Additional reporting by agencies.
