Thousands of people have taken to the streets of Argentina's capital, Buenos Aires, in protest at the government of Cristina Fernandez de Kirchner.
Opposition activists used social networks to mobilise the march, which they said was one of the biggest anti-government protests in a decade.
Those gathered said they were angry at rising inflation, high levels of crime and high-profile corruption cases.
President Fernandez was re-elected by a landslide to a second term in 2011.
Her approval ratings have since dropped and protests against some of her policies have mounted.
Official figures say inflation is at 12%, but analysts say it is probably much higher.
The International Monetary Fund warned Argentina in September that unless it produced reliable growth and inflation data by December, it could face sanctions.
Protesters also voiced their objections to restrictions introduced last year, and further sharpened this year, on the purchase of dollars, which have made it harder for Argentines worried about inflation to trade in their currency.
The government says the slowdown of the Argentine economy is the fault of the global financial crisis rather than its policies.
Supporters of President Fernandez say the protests are driven by people from the middle and upper class worried about losing their privileges.
They point to policies supporting the poor, such as cash payments to the unemployed, as the real achievements of her government.