[1] Elections were not required until September 2011, but on 2 September 2009 Prime Minister Kostas Karamanlis of New Democracy announced that he would request President Karolos Papoulias dissolve Parliament and call elections.

The result was a victory for the opposition PASOK party led by George Papandreou, who became the new prime minister.

New Democracy lost 61 of its 152 seats, with its vote share dropping by over 8 percentage points.

The initial results of the exit poll conducted jointly by pollsters Alco, GPO, MARC, Metron Analysis, MRB, Opinion, and RASS were made public at 7 PM Eastern European DST: The revised results of the exit poll conducted jointly by pollsters Alco, GPO, MARC, Metron Analysis, MRB, Opinion, and RASS were made public at 8:50 PM Eastern European DST.

The margin of error claimed is less than 0.5%: The statistical projections by Singular Logic and the Ministry of Interior, based on actual returns, were made public at 9 PM Eastern European DST.