Spanish voters are going back to polls after the country’s four main parties failed to break the political deadlock from December’s inconclusive general election.
More than 36 million of voters are called on to cast their ballot.
Opinion polls have suggested that June 26 election may still not overcome the stalemate.
Spain’s conservative Popular Party (PP) is tipped to win, but to fall short of a parliamentary majority.
Polls indicate the left-wing Unidos Podemos (United We Can) alliance is edging ahead of the Socialists (PSOE) for second place.
The center-right, pro-business party Ciudadanos (Citizens) is forecast to take fourth place.
Analysts say many voters are disillusioned and a high turnout is not expected.
December’s election was a watershed for Spain, because the PP and the PSOE had previously alternated in power since the restoration of democracy in the 1970s.
Unidos Podemos and other leftists argue that the PP, under acting PM Mariano Rajoy, has been discredited because of austerity and the chronic unemployment that has plagued Spain since the 2008 financial crisis.
The PP, however, says the country’s improved economic performance is proof that its policies have worked.
PM Mariano Rajoy said it was “important to convey a message of institutional and economic stability”.
Meanwhile, Unidos Podemos leader Pablo Iglesias said Europe had to “change course”, adding: “No-one would want to leave Europe if it were fair and united.”
Polls open at 07:00 GMT and close at 18:00 GMT with results expected two to three hours later.