Spain's King Felipe dissolved parliament on Tuesday and called a parliamentary election for June 26, the second in six months after an inconclusive ballot in late 2015 left its political landscape fragmented.
The new ballot follows four months of fruitless coalition talks between Spain's four main parties, including the conservative People's Party (PP) of acting prime minister Mariano Rajoy, which won the most votes in December but lost its majority.
"Let's hope we've all learned our lesson and that the next parliament reaches an agreement (on forming a government) as soon as possible," speaker Patxi Lopez told a news conference, confirming the king had signed the election decree.
Conducted against a backdrop of economic hardship and with a political elite tainted by corruption claims, the previous election marked the end of the dominance of the two traditional parties, the PP and the Socialists, that have governed Spain since its transition back to democracy in the mid-1970s.
Their power base was eroded by the emergence of two newcomers, anti-austerity Podemos ("We Can") and centrist Ciudadanos ('Citizens').
During a series of negotiations, the quartet of party leaders failed to bridge significant policy gaps, including how to manage the economy and how much autonomy to grant regional powerhouse Catalonia.
Opinion polls suggest the re-run may well also end in stalemate, and politicians are bracing for a rise in abstention among frustrated voters.
Some of the parties are already considering alliances.
Podemos may team up with the former communists of Izquierda Unida ("United Left"), which would help unite the vote on the left. That may pose a strong challenge to the Socialists, which came second in the December vote.
Podemos finished third and Ciudadanos fourth.