Riot police in the Greek capital have used tear gas and a water cannon to disperse protesters who were throwing stones and gasoline bombs.
Some 70,000 people gathered in Athens on November 7 to protest ahead of a key vote on a new round of austerity measures.
It was the second day of the two-day strike organized by labor unions.
Parliament is due to vote on 13.5 billion euros ($17.5) worth of pension and salary cuts and tax hikes international creditors are demanding before handing over new loans to keep Greece from going into bankruptcy.
Only a small number of the protesters clashed with police but it was the latest unrest in Greece, where the official unemployment is now at 25 percent and among youth has reached more than 50 percent.
Based on reporting by AP and AFP