Czech Prime Minister Vladimir Spidla resigned Saturday from his posts as head of government and head of the Social Democratic party, Czech CT television said Saturday.
Spidla earlier Saturday only narrowly won a confidence vote within his party, which suffered a embarrassing rout in European Parliament elections earlier in the month.
The move signals the downfall of the centre-left coalition government led by the Social Democrats (CSSD) since 2002.
Pressure had been mounting on Spidla from within the CSSD to step down as party chairman in favour of Stanislav Gross, the deputy prime minister and interior minister, as the party's popularity continues to plummet.
In the new EU member state's election on June 13, the CSSD finished fifth and won just two of the country's 24 seats.
And according to a poll released this week, it would win less than 14 percent of votes if elections were held now, while the main opposition party, the eurosceptic Civic Democrats (ODS), would win over 40 percent and the Communists 18 percent.
The party has been split into factions over the austerity measures undertaken by Spidla as part of reforms to ready the Czech Republic for European Union membership.