Changes to the electoral system of the Chamber of Deputies and of the Senate of the Republic. Delegation to the Government for the determination of single-member and multi-nominal electoral districts.
The law regulates the election of the Chamber and Senate, replacing Porcellum of 2005 and Italicum of 2015, both modified by the Constitutional Court of Italy after judging them to be partly unconstitutional.
On 8 October 2026, the Chamber of Deputies gave its final approval to a new electoral law which assigns seats on the basis of proportional representation with a majority bonus, repealing the Rosatellum.
As a consequence of the result of the 2016 Italian constitutional referendum, in which the Senate reform was rejected, the two chambers of the Italian Parliament ended up with two different electoral laws, which lacked uniformity. As a matter of fact, the electoral law for the Chamber of Deputies passed by Matteo Renzi's government, the so-called Italicum, based on a strong winner-take-all principle, was still in effect, whereas in the Senate a pure proportional system (the remnants of the so-called Porcellum, the electoral law approved by the cabinet of Silvio Berlusconi in 2005 and then declared extensively unconstitutional by the Constitutional Court in January 2014) was in force. The two systems differed on several aspects, among which the possibility of forming coalitions before the elections (only allowed at the Senate) and the election thresholds.
In June 2017, the Democratic Party together with the Five Star Movement, Forza Italia and Northern League agreed on a law, known as Tedeschellum, which was based on a similar system to the one used in Germany. However, the agreement among the four parties did not survive a secret-ballot vote during the first reading at the Chamber of Deputies and the bill was put aside.
After few weeks Ettore Rosato, the leader of the group of the Democratic Party at the Chamber of Deputies, proposed a new bill based on a mixed system, with half of the seats allocated using the first-past-the-post and the other half using a proportional allocation. The bill was not popular in its original version, since several opposition parties considered the number of seats allocated with the FPTP system too high.
A later and revised version of the Rosatellum, known as Rosatellum bis was approved by PD, FI, LN, AP and ALA in October 2017, becoming the new electoral law for both the houses of the Parliament.
Main characteristics and operation
The national elections use a mixed single vote into a parallel voting system, with 36.825397% of seats allocated using a first-past-the-post electoral system and 63.174603% using a proportional method (the latter including the seats allocated to Italians abroad), with one round of voting. The Senate and the Chamber of Deputies do not differ in the way the proportional seats are allocated, both using the largest remainder method of allocating seats.
a small, variable number of senators-for-life include former presidents of the Republic and no more than 5 other persons appointed for life by a president of the Republic, according to special constitutional provisions (scientists, writers, artists, social workers, politicians, tycoons).
The Senate is elected on a single ballot. The ballot includes the district's member, on a purely plurality basis and the parties and party-lists were listed that supported him, which was used to determine the proportional seats, with a 3% minimum threshold for party representation.
Following the 2020 referendum, the Chamber of Deputies had 400 members, of whom
147 are elected in single member districts.
245 are elected by proportional representation.
8 are elected by the Italians abroad.
As the Senate, the Chamber of Deputies is elected on a single ballot.
The complicated mechanism known as scorporo, which was used to tabulate PR votes in the Mattarellum, was abolished in the new electoral law.
The law also re-introduced a closed list system for the party lists on the second ballot, i.e., excluding voters from the decision as to which members of that party would enter parliament, thereby guaranteeing reelection of party leaders whose popular support was rapidly declining (new elections were to be held once the new electoral law was fully implemented).
Ballot paper
The voting paper
The ballot, which is a single one for the first-past-the-post and the proportional systems, shows the names of the candidates to single-member constituencies and, in close conjunction with them, the symbols of the linked lists for the proportional part, each one with a list of the relative candidates.
Voters will be able to cast their vote in three different ways:
Drawing a sign on the symbol of a list: in this case the vote extends to the candidate in the single-member constituency which is supported by that list.
Drawing a sign on the name of the candidate of the single-member constituency and another one on the symbol of one list that supports the candidate: the result is the same as that described above; panachage is not permitted, meaning voters cannot vote simultaneously for a candidate in the FPTP constituency and for a party list which is not linked to that candidate.
Drawing a sign only on the name of the candidate for the FPTP constituency, without indicating any list: in this case, the vote is valid for the candidate in the single-member constituency and also automatically extended to the list that supports them; if that candidate is however connected to several lists, the vote is divided proportionally between them, based on the votes that each one has obtained in that constituency.
Law 51/2019 was meant to adapt the Rosatellum to a reduction of the number of seats in both houses of the Italian Parliament. It became law on 26 June 2019. It has been called a riformina elettorale, or little electoral reform.
A constitutional amendment procedure was initiated during the 18th legislature by the Five Stars Movement, to cut the size of both houses by more than a third (from 630 and 315 members, to 400 and 200).
To avoid incompatibility with the proposed amendment, the 2019 law adapts the Rosatellum law, and sets fractions for each type of seat (proportional or majoritary) instead of exact numbers. The ratio of single-winner districts over the total number of seats in Rosatellum was equal to 3/8 in both houses, and the law 51/2019 retains those proportions.
On the 9 January 2020, Giuseppe Brescia, President of the lower house's Constitutional Affairs Committee, submitted bill AC 2329 (nicknamed Germanicum) that would replace Rosatellum with a system based on proportional representation. The bill would abolish single member constituencies, end the use of joint lists and increase the threshold from three to five percent nationally, while creating the 'right of tribune' where if a party did not reach the national threshold they could gain representation if they earned a quotient in at least three constituencies in two regions in the Chamber and in the Senate the party would need to receive a quotient in a constituency. Seats in the Chamber would firstly be apportioned on national results then subsequently into multimember constituencies, while in the Senate the process is similar but seats are first apportioned regionally, with both Houses using the Imperiali quota.
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