The Czech Republic's centre-right minority government has lost a vote of no-confidence midway through the country's six-month EU presidency.
Four rebel MPs voted with the opposition Social Democrats and Communists against PM Mirek Topolanek.
Mr Topolanek said he would step down, but correspondents say it is unclear how long he will remain in the post.
The European Commission said it was confident the Czech Republic could continue its EU role effectively.
Social Democrat leader Jiri Paroubek said ahead of the vote that the government could "complete the Czech EU presidency or its substantial part".
However, Mr Topolanek has ruled out the idea of a caretaker government until June, when the EU presidency passes to Sweden.
According to the constitution, Czech President Vaclav Klaus must decide who to choose to form a new administration. If three attempts to do so fail, early elections will be called.
Tuesday's no-confidence vote in the lower house followed accusations that one of Mr Topolanek's advisers had attempted to pressure its public TV channel into dropping a programme critical of a former Social Democratic MP who had decided to back the coalition.