The leader of Greece's Golden Dawn party, Nikos Michaloliakos, and more than 70 party members will be tried on charges including murder and belonging to a criminal group, officials say.
All 18 of the far-right party's MPs in the previous Greek parliament are among the defendants.
The crackdown follows an investigation into the 2013 murder of an anti-racist rapper by a Golden Dawn supporter.
The anti-immigrant party came third in January's elections with 6.3%.
Golden Dawn says it has no involvement in any violent activities and rejects the charges.
But it has also been linked to the murder of a Pakistani immigrant and beatings of political opponents.
Nazi paraphernalia has been found at MPs' houses and witnesses interviewed have talked of party "hit squads" formed to attack rivals.
Golden Dawn capitalised on the financial crisis, its violently anti-immigrant rhetoric winning votes among an ultranationalist fringe, says the BBC's Mark Lowen in Athens.
He says that now a new radical-left government is in power, there will be added determination to speed up the judicial process.
It is not yet clear whether the party's MPs will be allowed to sit in parliament until the trial begins.
A total of 72 people will stand trial on a date yet to be announced, judicial sources said.
Several of the lawmakers, including party leader Nikos Michaloliakos, are in pre-trial detention.
Most of the defendants will be tried for being part of a criminal organisation - a serious offence in Greece - while others are accused of crimes ranging from murder to conspiracy to murder, possession of weapons and racist violence, according to AFP news agency.
It comes after an investigation into the 2013 murder of a left-wing, anti-racist rapper, Pavlos Fyssas. A man held for the stabbing claimed to be a Golden Dawn supporter, though the party denied any link to him.
Some of the defendants, who include police officers, face sentences of up to 20 years in prison.
Prosecutor Isidoros Doyiakos, who headed the investigation into Golden Dawn's activities, said the organisation aimed "to propagate and impose its political beliefs and theories through violence", according to Reuters.