Following are the main parties running in Sunday's general election in Greece:
Leftist Leader: Alexis Tsipras, 41.
The coalition of left-wing and radical left parties, SYRIZA was founded in 2004 and officially launched as a party in 2012.
Its leader, Alexis Tsipras, was elected in 2008 becoming the youngest political leader in the history of modern Greece.
During the crisis, the anti-bailout party's ratings rose rapidly. Tsipras was elected prime minister in January on the promise to end austerity and keep Greece in the eurozone.
His party secured 36.3 percent of the vote – 149 lawmakers in the 300 seat-parliament – and allied with the small right-wing Independent Greeks' party.
During his negotiations with the country's international creditors, Greece reached the brink of bankruptcy. In July, Tsipras called a referendum on a bailout offer, a move which led to capital controls.
The vote returned a resounding “no” to austerity but Tsipras finally capitulated to the tough terms of a third bailout deal to keep Greece in the eurozone.
The bailout passed by parliament but was rejected by 44 SYRIZA lawmakers, forcing Tsipras to resign a few days later and call a snap election.
SYRIZA has rejected the possibility of an alliance with the conservative New Democracy.
Conservative Leader: Vangelis Meimarakis, 61.
The conservative party was founded by prominent political figure Constantinos Karamanlis in 1974 after the fall of the military junta.
It has been Greece's main centre-right party and, along with Socialist rival (PASOK), has dominated Greece's political landscape for decades.
In 2012, under then-leader Antonis Samaras, it formed a coalition government that ruled until he failed to get parliament to approve his choice for president leading the country to snap elections. His party, which had promised to continue with its plan to exit the bailout, was defeated by SYRIZA on Jan. 25.
Under its interim leader Vangelis Meimarakis, New Democracy has managed to catch up with SYRIZA and the two parties are running neck-and-neck in opinion polls.
Meimarakis has said New Democracy will seek an alliance with SYRIZA or pro-European parties if he wins the election, but has ruled out close cooperation with Tsipras.
Far-right Leader: Nikos Michaloliakos, 57 The extreme right-wing political party remained on the fringes for years after it was founded in 1985. It entered parliament for the first time in 2012 with nearly 7 percent, tapping into Greeks' anger at austerity and high unemployment.
Its leader Nikos Michaloliakos and other top figures were arrested in 2013 and charged with belonging to a criminal group, weeks after the stabbing of anti-racism rapper Pavlos Fyssas by a party supporter.
The party, which has most support among Greek youth angered by SYRIZA's bailout U-turn, is in a race for third place in Sunday's election with centrist to Potami, PASOK and the Communist KKE.
Communist Leader: Dimitris Koutsoumbas, 60.
Founded in 1918, the KKE was mostly outlawed until the fall of Greece's military junta in 1974. With a hammer and sickle in its logo, the party still espouses Marxist-Leninist ideology two decades after the collapse of the Soviet Union.
Its members over the decades, often persecuted by right-wing regimes, included many who fought as partisans during the Nazi occupation of Greece.
The anti-bailout party blames both SYRIZA and New Democracy for committing to unpopular reforms, pension cuts and tax hikes.
It won 5.47 percent in January and 13 seats in parliament.
Centrist Leader: Stavros Theodorakis, 52.
The centrist To Potami party was founded in February 2014 by television journalist Stavros Theodorakis. It entered parliament in January with 6 percent of the vote.
It supported the country's third bailout in August. Potami hopes to play kingmaker role as a pro-euro ally for either SYRIZA or New Democracy.
Socialist Leader: Fofi Gennimata, 50.
Founded by Andreas Papandreou in 1974, PASOK came to power with about 44 percent when Greece's crisis broke out in 2009 under George Papandreou's leadership. It also participated in the coalition led by New Democracy that ruled from June 2012 to January 2015.
Its voters gradually abandoned it during the crisis, mainly because it supported the country's first two bailouts, and has seen its ratings dropping to 4-6 percent.
Its leader Fofi Genimata formed an alliance with the small center-left DIMAR party in the run-up to Sunday's election.
Leader: Panos Kammenos, 50.
The right-wing party was founded in 2012 when its leader, Panos Kammenos, and ten others broke away from New Democracy in protest at the second bailout. It has often attacked the country's lenders for the austerity measures they have imposed.
The Independent Greeks got 13 seats with 4.75 percent of the votes in January's elections and became SYRIZA's coalition partner. It is polling around 3 percent, the lower threshold for parliamentary representation.
UNION OF CENTRISTS
Leader: Vassilis Leventis 63.
The centrist party was founded in 1992 by Vassilis Leventis, who has gained a following by publishing his own newspaper, railing against an establishment he says has 'poisoned' Greece.
Polls show it will win about 3.5-4 percent of the vote.
Radical left Leader: Papayiotis Lafazanis 63.
The party has been set up by Lafazanis, a vocal critic of the third bailout program, and 25 lawmakers that broke away from SYRIZA in August. It is polling around 3 percent.