The organisation, which recently accepted political responsibility for the murder of a left-wing rapper, are the third largest party in the country.
The rally, held in historic Syntagma Square, was literally painted red with SYRIZA flags and shirts, albeit not as many as January's final rally or the 'No' rally prior to July's referendum.
For the third time in eight months, people are preparing to head to the polling stations.
A personal look into how austerity measures and the economic crisis have affected Greeks in Chania, Crete, some of Greece's most fervent anti-austerity citizens.
Tension and disappointment dominated the Greek parliament as it prepared to vote on a set of austerity measures so tough, they'd have Thatcher dancing in her grave.
Paul Mason's foreword from The Global Minotaur: America, Europe and the Future of the Global Economy by Yanis Varoufakis, Greece's ex-finance minister who resigned this morning.
Here's how the capital city looked in the hours following the referendum result.
"Don't get me wrong: I don't think voting yes will improve Greece's prospects."
"I don't think it'll change anything, but at the same time, enough is enough. Voting no is a matter of dignity. It's a way of hitting back."
We went to the port of Piraeus in Athens and asked people how come they're taking a vacation in the middle of it all.
Banks have been ordered to re-open so that pensioners without debit cards can withdraw small amounts of cash.