Italy's centre-left leader Pier Luigi Bersani said talks to form a new government have failed.
Mr Bersani told reporters that some of the conditions set by other parties during nearly a week of talks were "unacceptable".
He informed President Giorgio Napolitano that his attempts to form a government failed. It will be up to Mr Napolitano to decide the next step.
The failure makes more likely a possible technical government with a well-defined mission to take on urgent tasks to protect the Italian economy.
Mr Bersani has been in consultations since being approached to conduct negotiations last Friday.
But the anti-establishment 5 Star Movement made clear that it would not back Mr Bersani or any established party.
Mr Bersani's coalition controls the lower house but not the Senate. He excluded an alliance with Silvio Berlusconi's centre-right forces.