This list of Prime Ministers of Italy lists each Prime Minister in order of term length. This is based on the difference between dates; if counted by number of calendar days all the figures would be one greater.
Of the 57 Prime Ministers, 8 served more than 5 years while 18 served less than 1 year.
Benito Mussolini is the only person to have served as Prime Minister for more than 20 years. Tommaso Tittoni served as Prime Minister for only 15 days.