The Senate of the Republic (Senato della Repubblica), or simply the Senate (Senato), is the upper house of the bicameral Italian Parliament (the other being the Chamber of Deputies). The two houses together form a perfect bicameral system, meaning they perform identical functions, but do so separately. Pursuant to the Articles 57, 58, and 59 of the Italian Constitution, the Senate has 200 elective members, of which 196 are elected from Italian constituencies, and 4 from Italian citizens living abroad. Furthermore, there is a small number (currently 6) of senators for life (senatori a vita), either appointed or ex officio. It was established in its current form on 8 May 1948, but previously existed during the Kingdom of Italy as Senato del Regno (Senate of the Kingdom), itself a continuation of the Senato Subalpino (Subalpine Senate) of Sardinia established on 8 May 1848. Members of the Senate are styled Senator or The Honourable Senator (Italian: Onorevole Senatore) and they meet at Palazzo Madama, Rome.
Article 57 of the Constitution of Italy originally established that the Senate of the Republic was to be elected on a regional basis by Italian citizens aged 25 or older (unlike the Chamber of the Deputies, which was elected on a national basis and by all Italian citizens aged 18 or older). No region could have less than 7 senators, except for the two smallest regions: Aosta Valley (1 senator) and Molise (2 senators). From 2006 to 2020, 6 out of 315 senators (and 12 out of 630 deputies) were elected by Italians residing abroad.
After two constitutional amendments were passed respectively in 2020 (by constitutional referendum) and 2021, however, there have been changes. The Senate is still elected on a regional basis, but the number of senators was reduced from 315 to 200, who are now elected by all citizens aged 18 or older, just like deputies (themselves being reduced from 630 to 400). Italians residing abroad now elect 4 senators (and 8 deputies).
The remaining 196 senators are assigned to each region proportionally according to their population.