What had started as a general strike in Greece, developed into running battles between protesters and police dressed in riot gear in areas of Athens.
Clashes erupted close to the Parliament buildings where deputies were preparing to vote on new austerity measures.
The mood was one of fury as black clouds of smoke from petrol bombs hung over Syntagma Square, the scene of violent clashes in June.
Seven thousand officers had been assigned to the capital to deal with the anticipated trouble.
There were several injuries from minor burns while there were reports the violence spread beyond the main rally which police estimate attracted more than 100,000.
It is understood it was a group of hard core younger demonstrators who fought with the police while older protesters moved away from the trouble.