Under the
1978 Constitution, the Spanish were conceived as an
imperfect bicameral system. The
Congress of Deputies held greater legislative power than the
Senate, having the ability to grant or withdraw confidence from a
prime minister and to override Senate
vetoes by an
absolute majority. Nonetheless, the Senate retained a limited number of specific functions—such as
ratifying international treaties, authorizing cooperation agreements between
autonomous communities, enforcing
direct rule, regulating interterritorial compensation funds, and taking part in
constitutional amendments and in the appointment of members to the
Constitutional Court and the
General Council of the Judiciary—which were not subject to override by Congress.
Date The term of each chamber of the —the Congress and the Senate—expired four years from the date of their previous election, unless they were
dissolved earlier. The election
decree was required to be issued no later than 25 days before the scheduled expiration date of parliament and published on the following day in the
Official State Gazette (BOE), with
election day taking place 54 days after the decree's publication. The
previous election was held on 28 April 2019, which meant that the chambers' terms would have expired on 28 April 2023. The election decree was required to be published in the BOE no later than 4 April 2023, setting the latest possible date for election day on 28 May 2023. The prime minister had the prerogative to propose the
monarch to dissolve both chambers at any given time—either jointly or separately—and call a
snap election, provided that no
motion of no confidence was in process, no
state of emergency was in force and that dissolution did not occur before one year after a previous one. Additionally, both chambers were to be dissolved and a new election called if an
investiture process failed to elect a prime minister within a two-month period from the first ballot. Barring this exception, there was no constitutional requirement for simultaneous elections to the Congress and the Senate. Still, as of , there has been no precedent of separate elections taking place under the 1978 Constitution. The were officially dissolved on 24 September 2019 with the publication of the corresponding decree in the BOE, setting election day for 10 November and scheduling for both chambers to reconvene on 3 December.
Electoral system Voting for each chamber of the was based on
universal suffrage, comprising all
Spanish nationals over 18 years of age with full
political rights, provided that they had not been
deprived of the right to vote by a final
sentence. Additionally,
non-resident citizens were required to
apply for voting, a system known as "begged" voting (). The Congress of Deputies had a minimum of 300 and a maximum of 400 seats, with electoral provisions fixing its size at 350. Of these, 348 were elected in 50
multi-member constituencies corresponding to the
provinces of Spain—each of which was assigned an initial minimum of two seats and the remaining 248 distributed in proportion to population—using the
D'Hondt method and
closed-list proportional voting, with a three percent-
threshold of valid votes (including
blank ballots) in each constituency. The remaining two seats were allocated to
Ceuta and
Melilla as
single-member districts elected by
plurality voting. The use of this electoral method resulted in a higher
effective threshold depending on
district magnitude and vote distribution. As a result of the aforementioned allocation, each Congress multi-member constituency was entitled the following seats: 208 Senate seats were elected using
open-list partial block voting: voters in constituencies electing four seats could choose up to three candidates; in those with two or three seats, up to two; and in single-member districts, one. Each of the 47 peninsular provinces was allocated four seats, while in insular provinces—such as the
Balearic and
Canary Islands—the districts were the islands themselves, with the larger ones (
Mallorca,
Gran Canaria and
Tenerife) being allocated three seats each, and the smaller ones (
Menorca,
Ibiza–
Formentera,
Fuerteventura,
La Gomera,
El Hierro,
Lanzarote and
La Palma) one each. Ceuta and Melilla elected two seats each. Additionally, autonomous communities could appoint at least one senator each and were entitled to one additional seat per million inhabitants. The law did not provide for
by-elections to fill
vacant seats; instead, any vacancies arising after the proclamation of candidates and during the legislative term were filled by the next candidates on the
party lists or, when required, by designated
substitutes.
Outgoing parliament The tables below show the composition of the
parliamentary groups in both chambers at the time of dissolution. ==Candidates==