On the 30 July deadline, a total of eleven candidates officially registered their candidacy: Walter Veltroni, Rosy Bindi, Enrico Letta, Furio Colombo, Marco Pannella, Antonio Di Pietro, Mario Adinolfi, Pier Giorgio Gawronski [it], Jacopo G. Schettini, Lucio Cangini and Amerigo Rutigliano.

Of these, Pannella and Di Pietro were stopped because of their involvement in external parties, whereas Cangini and Rutigliano did not manage to present the necessary 2,000 valid signatures for the 9pm deadline, and Colombo's candidacy was instead made into hiatus in order to give him 48 additional hours to integrate the required documentation; Colombo later decided to retire his candidacy citing his impossibility to fit with all the requirements.

[13] He ran in a joint ticket with deputy-leadership candidate Dario Franceschini, Olive Tree speaker at the Chamber of Deputies.

[14] Enrico Letta was the incumbent undersecretary in the Prodi II Cabinet, and a leading member of Democracy is Freedom – The Daisy.

On the night of 30 July, a few minutes shy of the deadline, incumbent Minister of Infrastructures and Italy of Values party leader Antonio Di Pietro was officially unveiled as entering the race.

[20] His candidacy was initially made into hiatus by the Organizing Committee due to his failure in presenting the original copy of many of the requested 2,000 signatures.