Italian lawmakers are expected to participate in a second round of voting Tuesday, after failing to elect a new president in the first round of secret balloting Monday.
The incoming center-left coalition and its opponents could not agree on a compromise candidate.
Supporters of newly-elected Prime Minister Romano Prodi proposed former Communist Giorgio Napolitano as their choice to replace President Carlo Azeglio Ciampi.
But the candidate was rejected by outgoing Prime Minister Silvio Berlusconi, who is backing one of his own political advisors, Gianni Letta.
To win, a candidate needs to receive the votes of two-thirds of the more than 1,000 delegates. After three unsuccessful ballots, a simple majority of the 1,000 delegates decides the winner.
Italy's presidency is mostly ceremonial, but the next president must take office before Mr. Prodi can form a government.