control health and education budgets. More than 35 million people were registered to vote.
Podemos and Ciudadanos have surged over the past year to occupy third and fourth place in the polls behind the Popular Party and the mainstream opposition Socialists.
Those two parties have taken turns running Spain for more than 30 years.
“There is no doubt that a majority of Spaniards want change. What they want now are governments that make pacts and engage in dialogue,” said Jose Pablo Ferrandiz from major pollster Metroscopia.
“That is truly something new in Spain. We are not used to coalition governments.”
The polls also indicated a marked rise in turnout was likely, driven by young voters.
“This is a historic campaign for political change in Spain, just like during the transition” from dictatorship in the 1970s, Ciudadanos leader Albert Rivera said.
Polls have consistently shown the PP losing support overall.
“In 2011 we demonstrated on the town squares. In 2015 we will throw them out of power,” Podemos leader Pablo Iglesias said.
Spain’s economic growth is gradually improving, but the unemployment rate was at more than 23 percent at the last count and anti-austerity campaigners say the recovery is not reaching the poorest.
Sunday’s vote is an important warm-up for Prime Minister Mariano Rajoy as he fights to stay in office in the general election due around November.
He warns that ejecting the PP from office could disrupt Spain’s economic recovery.
“This is not a time to experiment,” he said. “You cannot experiment with the interests of the Spanish people.”
Analysts say a Podemos surge could undermine foreign investors’ confidence in Spain’s financial stability, like Syriza’s rise to power in Greece.
But Ciudadanos has offered them a more market-friendly alternative and could act as an “important power broker” to keep Spain’s economic reforms on track, said analyst Christian Schulz of German bank Berenberg.