More than 450 people have been arrested after police using tear gas and water cannon clashed with protesters in the Chilean capital, Santiago.
The worst violence broke out when police tried to prevent demonstrators marching on the presidential palace.
Dozens of people were injured, among them a socialist senator.
The main trade union federation called the protest, saying the government's free market economic policies have meant poorer conditions for workers.
Demonstrations took place in several cities around Chile, but outside the capital they were mostly peaceful.
Appeal for dialogue
There were clashes throughout the day in Santiago, where riot police tried to stop demonstrators moving on the government palace, La Moneda.
The marchers threw stones, while the police responded with teargas and water cannon.
Local television showed Socialist Senator Alejandro Navarro with blood streaming from a head wound after he was struck by a police officer. A police spokesman later apologised.
Trade union leaders promised to continue their protests.
"We're going to continue behaving badly as long as there is injustice in this country. We're happy people are here because it means Chile is defending itself." said Maria Rozas, vice-president of the trade union federation, CUT.
President Michelle Bachelet said there was space within Chilean democracy for people to express their demands but it should be done peacefully.
Democracy, she added, did not need disorder and violence.
Chile has one of the strongest economies in Latin America and has one of the lowest poverty levels in the region.
The BBC's Horacio Brum in Santiago says about three million workers, roughly half the workforce, earn the minimum age of $260 (£130) a month.
"But a family of four, without thinking of pension plans and health insurance etc, needs about $1000 to $1,500 a month to live comfortably."
The popularity of President Bachelet's government has slumped in recent months, with Chileans taking to the streets to demonstrate, among other things, against unemployment, the education system and poor public transport.