Italian electoral law of 2015

The Italian electoral law of 2015, also known as Italicum, was an Italian electoral law passed in 2015. The law, which came into force on 1 July 2016, regulated only the election of the Chamber of Deputies, replacing the Italian electoral law of 2005, which had been ruled partly unconstitutional by the Constitutional Court of Italy in December 2013. It provided for a two-round system based on party-list proportional representation, including a majority bonus and a 3% election threshold. Candidates would have run in 100 multi-member constituencies using open lists. The largest party which won over 40% of the vote would automatically win a majority of seats; if no party won 40% of seats, a second round of voting would be held between the two largest parties, with the winner of the second round winning a majority of seats. The name "Italicum" was coined in 2014 by Democratic Party secretary and later Prime Minister of Italy, Matteo Renzi, who was one of the legislation's main proponent.

The law was written under the assumption that major constitutional reforms would have taken place by the time it came into force. The failure of the reforms in the 2016 Italian constitutional referendum created unforeseen complications, as electoral law for the Chamber of Deputies and Senate of the Republic were not harmonised. This was compounded by a January 2017 Constitutional Court ruling finding the Italicum partly unconstitutional. In October 2017, the Italicum was repealed by the Italian Parliament and replaced by the Rosatellum. The Italicum is the first and only electoral law to have been approved by the Italian Parliament but never used in a general election.