Protest groups joined forces under the slogan "Citizens' Tide, 23F," referring to the Feb. 23, 1981, attack by the armed forces on the parliament. Organizers said that Spain "is under a financial coup" and called on people to march against what they said was government favoritism toward financial institutions at the expense of ordinary citizens.
Many Spaniards have been enraged by austerity cutbacks and tax hikes introduced by Prime Minister Mariano Rajoy in a bid to reduce the deficit, ease market pressures on government borrowing and try and avoid a full financial bailout. Spain is in its second recession in three years and has 26 percent unemployment.
"We are all indignant and think the measures adopted by the government are wrong, especially considering they did not say they would adopt them before the elections when people voted them into office," said Sergio Sosa, a 46-year-old employee of Iberia airlines, which is planning 3,800 job cuts.
Similar protests were planned in 80 Spanish cities. News agency Europa Press reported that thousands of demonstrators had gathered as far afield as in the city of Las Palmas on the Atlantic island of Gran Canaria.
Rajoy was elected in a landslide late 2011 after saying during his election campaign that he had no plans to raise taxes or cut pensions.
Around 2,000 riot police guarded the columns of protesters that marched toward parliament from four points in Madrid.
Protest organizers had asked people to dress in white, green, red, yellow, black, blue or purple to represent their interests, such as health services, ecology or fire services, among others.
Regional Interior Ministry officials said late Saturday they did not have estimates of the number of people demonstrating. They said the protests were peaceful.