Spaniards had been patient during four years of economic trouble, but this wore out in the run-up to the elections when tens of thousands of mostly young protesters took to the streets in cities around the country.
EYES ON GENERAL ELECTION
The PP is expected to call for early elections, but does not have enough seats in parliament to win a vote of no confidence.
The Socialists must choose in the next few months a successor to Zapatero, who has said he will not run for a third term. Deputy Prime Minister Alfredo Perez Rubalcaba and Defence Minister Carme Chacon are both contenders.
Analysts said Zapatero wants to hang on as long as he can, giving the economy more time to pick up and boosting the Socialists' chances to win again or at least to limit PP gains.
"They're waiting for the rain to stop. If the economy improves in the third quarter and unemployment also improves, they can say it's because of their economic reforms," said Antonio Barroso, analyst with Eurasiagroup consulting firm, who sees Zapatero remaining in office until March.
EURO ZONE CRISIS
The election took place against the backdrop of the euro zone debt crisis, which forced Zapatero to make steep spending cuts to fend off concerns that Spain would follow Greece, Ireland and Portugal into budget problems and a bailout.
The austerity measures have held back economic growth and some sectors are still destroying jobs.
Zapatero promised voters that no more austerity is in the works. A fresh round could provoke renewed protests.
At the same time he promised investors that he will not budge from a commitment to cut the budget deficit to 6 percent of Gross Domestic Product this year, but some experts questioned whether he will achieve this with the economy in the doldrums.
"There's a risk of everything becoming excessively politicised which will be detrimental for the economy," said Carlos Berzosa, professor of applied economy at Madrid's Complutense university.