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Spain is a democratic monarchy organized under three branches of government: executive, legislative and judicial. The legislative branch, called the Cortes Generales (Parliament), is bicameral, with a Congress of Deputies and a Senate. Bills follow a process set up by the Spanish Constitution; most commonly, bills are initiated by the Congress of Deputies, reviewed by the Senate, and promulgated by the King. Bills may also be proposed by the government, the Senate, autonomous communities’ parliaments, or through popular initiative.

I. Introduction

The 1978 Spanish Constitution (SC)[1] sets up the institutional and political organization of the country. It was adopted as a result of a consensus reached after decades of the dictatorship of Francisco Franco.[2]  It was approved in plenary sessions of the Congress of Deputies and the Senate on October 31, 1978, and ratified by the Spanish people via referendum by a broad majority of voters and electors on December 6, 1978.[3]   

Under the SC, sovereignty is vested in the Spanish people, from whom state powers are derived.[4]

Spain is a member of the European Union (EU) and as such it has assigned certain economic and political competences to EU institutions.[5] 

Under the SC, Spain is a constitutional parliamentary monarchy.  The King is the head of state, representing the State at the national and international level.  The Prime Minister is the head of the executive power and President of the Government.[6]  Spain has a unitary form of government, in that all powers ultimately vested in the central government,[7] although some powers are delegated by it to lower levels of government.  There are three different levels of government:  

  • Central government
  • Autonomous communities’ governments
  • Provincial and municipal governments

The central government is organized in three branches: The executive power; a bicameral Parliament known as the Cortes Generales,[8] which consists of the Congreso de los Diputados (Congress of Deputies)[9] and the Senado (Senate);[10] and the judiciary.[11]

The territorial organization of Spain includes seventeen autonomous communities (Andalucía; Aragón; Asturias (Principado de); Balears (Illes); Canarias; Cantabria; Castilla-La Mancha; Castilla y León; Cataluña; Comunitat Valenciana; Extremadura; Galicia; Madrid (Comunidad de); Murcia (Región de); Navarra (Comunidad Foral de); País Vasco; and Rioja (La).  In addition there are 2 autonomous cities: Ceuta and Melilla.[12]  In addition there are fifty provinces, which constitute electoral districts, spread out through the autonomous communities.[13]

Under the SC the State holds exclusive competence over the following matters:

i) Regulation of the basic conditions guaranteeing the equality of all Spanish nationals in the exercise of their rights and in the fulfilment of their constitutional duties;

ii) Nationality, immigration, emigration, status of foreigners, and the right of asylum;

iii) International relations;

iv) Defense and the Armed Forces;

v) Administration of Justice;

vi)  Commercial, criminal and penitentiary legislation; procedural legislation, taking into consideration the special features derived from the particularities of the substantive law adopted by the Autonomous Communities;

vii) Labor legislation;

viii) Civil legislation, taking into consideration the preservation, modi­fication and development by the Autonomous Communities of their civil laws, «fueros» or special laws, whenever these exist;

ix) Legislation on intellectual and industrial property;

x) Customs and tariff regulations and foreign trade;

xi) Monetary system: foreign currency, exchange and convertibili­ty; bases for the regulations concerning credit, banking and insurance;

xii) Legislation on weights and measures, determination of the official time;

xiii) Bases and coordination of general planning of economic activity;

xiv) General finances and the State Debt;

xv) Promotion and general coordination of scientific and techni­cal research;

xvi) External health measures; bases and general coordination of health matters; legislation on pharmaceutical products;

xvii) Basic legislation and financial system of the Social Security, taking into consideration the implementation of its services by the Auton­omous Communities;

xviii) Bases of the legal regime of the Public Administration and civil servants and  public officials, taking into consideration to the special features of the Autonomous Community’s own organiza­tions; legislation on compulsory expropriation; basic legislation on contracts and administrative concessions and the system of liability of all Public Administrations;

xix) Sea fishing;

xx) Merchant navy and the registering of ships; lighting of coasts and signals at sea; general purpose ports; general-purpose airports; control of air space, air traffic and transport; meteorological services and registration of aircraft;

xxi) Railways and land transport passing through the territory of more than one Autonomous Community; general communi­cations system; motor vehicle traffic; Post Office services and telecommuni­cations; air and underwater cables and radio communications;

xxii) Legislation, regulation and concession of water resources;

xxiii) Basic legislation on environmental protection, considering the powers of the Autonomous Communities to establish addi­tional protective measures; basic legislation on woodlands, forestry, and livestock trails;

xxiv) Public works of general benefit or whose execution affects more than one Autonomous Community;

xxv) Bases of the organization of mining and energy;

xxvi) Legal regime of production, sale, possession and use of arms and explosives;

xxvii) Basic rules on the press, radio and television and, in general, all the means of social communica­tion, taking into consideration the powers vested in the Autonomous Communities related to their development and implementation;

xxviii) Protection of Spain’s cultural and artistic heritage and national monuments against exportation and despoliation; museums, libraries and archives belonging to the State, taking into consideration its Autonomous Communities’ management;

xxix) Public safety, taking into consideration the power of the Autonomous Communities to create its own police forces;

xxx) Regulation of academic degrees and professional qualifica­tions;

xxxi) Statistics for State purposes;

xxxii) Authorization of popular consultations through referendums.[14]  

All matters that are not expressly assigned to the State under the SC may fall under the jurisdiction of the autonomous communities.  In case of conflict, the State’s laws shall prevail over those of the autonomous communities regarding all matters over which exclusive jurisdiction has not been conferred upon the latter.[15]

The autonomous communities may assume competences over the following matters:

i) Organization of their self-government institutions;

ii) Changes in the municipal boundaries within their territory;

iii) Town and country planning and housing;

iv) Public works within its own territory;

v) Railways, roads and transportation whose routes lie exclusively within the ter­ritory of the Autonomous Community;

vi) Ports of haven, recreational ports and airports and, in general, those which are not engaged in commercial activities;

vii) Agriculture and livestock;

viii) Woodlands and forestry;

ix) Environmental protection management;

x) Planning, construction and operation of hydraulic projects, canals and irrigation of benefit to the Autonomous Community; mineral and thermal waters;

xi) Inland water fishing, the shellfish industry and aquaculture, shooting and river fishing;

xii) Local fairs;

xiii) Economic development promotion of the Autono­mous Community;

xiv) Handicrafts;

xv) Museums, libraries and music conservatories of interest to the Autonomous Community;

xvi) Monuments of the Autonomous Communities;

xvii) Promotion of culture, research and, when applicable, the teaching of the language of the Autonomous Community;

xviii) Promotion and planning of tourism within its territory;

xix) Promotion of sports and use of leisure;

xx) Social assistance:

xxi) Health and hygiene;

xxii) Supervision and protection of its buildings and facilities; coordination and other powers relating to local police forces under the terms to be laid down by an organic law.[16]

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II. Parliament

Legislative power is entrusted to the Cortes Generales,[17] which is the official name of the Spanish Parliament. Cortes is a traditional name for a legislative body, which derives from medieval assemblies of various peninsular kingdoms; Generales denotes the nationwide representation of the Parliament.[18]

Members of Parliament are elected in universal, free, equal, direct and secret elections by the Spanish people in full exercise of their political rights.[19] They are elected for a four-year period.[20]

All members of Parliament have immunity for the opinions they express in the course of their functions.[21] No liability of any kind may be derived from those opinions.[22]

The Congress of Deputies is the chamber of popular representation, while the Senate serves as the chamber of territorial representation.[23]

Common functions of both the Congress of Deputies and the Senate include

  • passing legislation;[24]
  • approving the State budget, by passing the annual act setting forth revenues and expenditures;[25] and
  • supervising the actions of the government through different procedures such as  interrogations, interpellations, motions, and hearings.[26]

Members in both chambers are prohibited from belonging to both chambers simultaneously.[27]

The Constitution provides that members of both chambers enjoy the prohibition of imperative mandate (mandato imperativo), which means they are free to express themselves and vote their conscience without being subject to any instructions from electors or political parties.[28]

Parliamentary sessions normally run from February to June and from September to December.[29]

Each chamber is governed by its own internal rules and regulations.[30] Each chamber has the following offices:

  • President
  • Board (Mesa), which is the formal representative of each chamber as a body, in charge of its organization and internal work
  • Bureau of Spokesmen (Junta de Portavoces), which includes one representative of each parliamentary group and meets to set the order of business and agenda of the body[31]

Both chambers convene in plenary sessions and in committees.[32]  The chambers may delegate the approval of regular bills to standing legislative committees, although the plenary body may require debate and voting on any such delegated bill.[33]  The approval of bills involving constitutional reform, international affairs, organic and basic acts, and the budget cannot be delegated.[34]

The Congress of Deputies and the Senate and, when appropriate, both nouses jointly, may appoint committees on investigation on any matter of public interest.[35] Their findings are not binding on the courts, but their conclusions may be referred to the Public Prosecutor for further action when appropriate.[36]  It is mandatory to appear when summoned before Parliament, subject to penalties in cases of non-compliance.[37]

A. Congress of Deputies

The Congress of Deputies has a minimum of three hundred and a maximum of four hundred members.[38]  Its members are elected via proportional representation.[39]  The electoral district is the province.[40]  Each electoral province is allotted a minimum initial representation and the remainder is distributed in proportion to the population; the autonomous cities of Ceuta and Melilla are each assigned one deputy.[41]  All Spanish nationals with political rights have the right to vote and be elected.[42]  Deputies are elected to serve four-year terms.[43]  

The last election to the Congress of Deputies was on 26 June 2016.[44] The current XII Legislature (2016–present) includes the following political parties:

Parliamentary Group Popular (PP): 137

Parliamentary Group Socialista (PSOE): 85

Parliamentary Group Upodemos: 71

Parliamentary Group Ciudadanos: 32

Parliamentary Group Esquerra Republicana (ERC): 9

Parliamentary Group Basque (PNV): 5

Parliamentary Group Mixed: 11[45]

B. Senate

Senators are elected by universal, free, equal, direct and secret suffrage.[46] Senators are elected through a majority system, in which voters cast votes for individual candidates.[47]

The requirements to stand as a candidate and be elected senator are Spanish nationality, legal age, and not having been declared legally incapacitated.[48]

The presence of women in the Senate has increased since the electoral reform of 2007, which imposes a balanced number of men and women in the composition of candidate lists. Currently ninety-seven senators out of a total of 266 are female.[49]

The Senate has a territorial representation.[50] There are two ways to become a senator: election by provincial constituencies or appointment by regional parliaments.   

1.  Senators Elected by Provincial Constituencies

Each province elects four senators.  However, in the insular provinces, each island or group of islands is classed as an electoral constituency, with each of the larger islands (Gran Canaria, Mallorca and Tenerife) electing three senators and the remaining islands (Ibiza-Formentera, Menorca, Fuerteventura, Gomera, Hierro, Lanzarote and La Palma) electing one senator.  The populations of Ceuta and Melilla each choose two senators.[51]

2.  Senators Appointed by Regional Parliaments (Autonomous Community)

The appointment of senators by regional parliaments is carried out by means of indirect election, in the sense that they are not elected by the population but instead are appointed by the elected representatives of the population (the members of said parliaments).[52]

There is one senator for each autonomous community and another for every one million inhabitants. Therefore, the number of senators that make up this second group is variable, and the number has recently increased as a result of an increase in population.[53]

Following the June 26, 2016, election, the makeup of the Senate by party, including senators appointed by regional parliaments, was as follows:

Parliamentary Group Popular (PP): 149

Parliamentary Group Socialista (PSOE): 62

Parliamentary Group Upodemos: 20

Parliamentary Group Ciudadanos: 6

Parliamentary Group Esquerra Republicana (ERC): 12

Parliamentary Group Basque (PNV): 6

Parliamentary Group Mixed: 11

Total number of senators: 266[54]

C. Legislative Process

The legislative process in each chamber is governed by its own internal rules of procedure.[55]  The only occasions when there is joint action is for the adoption of decisions involving the Crown, such as the proclamation of the King, his heir, the provision of succession to the Crown when all the rightful lines have ended, and the appointment of the Regency.[56]

Legislation may be initiated by the government, the Congress of Deputies, the Senate, the assemblies of the autonomous communities, or through popular initiative.[57]

The government may present a bill, which first must be reviewed by the Council of Ministers (within the cabinet of the Executive Power); the Council of Ministers then submits the bill to the Congress of Deputies, accompanied by a statement setting out the necessary grounds and facts to enable them to reach a decision.[58]

The Congress of Deputies and the Senate submit bills pursuant to an approval process regulated in the standing orders of the houses.[59]

The legislatures of the autonomous communities may request that the government submit a bill before Congress.[60]

A popular initiative requires at least 500,000 authenticated signatures and cannot relate to certain matters, such as taxation, international affairs, or the prerogative of granting pardons.[61]

For ordinary laws, once a bill is proposed and accepted during a plenary session of the Congress of Deputies, it is debated by the members to determine whether it is accepted, rejected or amended.[62]  Once the text of the bill is approved, it is submitted by the President of the Congress of Deputies to the Senate, which then follows a similar procedure.[63]

With respect to organic laws—those that implement fundamental rights and public freedoms, approve the statutes of autonomous communities, approve the general electoral system, and other legislation designated as such[64]—the approval, amendment and repeal of bills require the vote of the majority of the Congress and the Senate.[65]

The legislative process generally concludes with the promulgation of the law by the King within fifteen days after the bill was approved by the Cortes Generales.[66] A law becomes effective twenty days after its publication in the Official Gazette, called Boletin Oficial del Estado (BOE), unless otherwise provided in the law.[67]

In general, international treaties and agreements are negotiated and signed by the government and ratified by the Cortes Generales, which must be immediately informed of the signature of all treaties.[68]  The following treaties require prior authorization of the Cortes Generales:

  • Treaties of a Political Nature
  • Treaties of a Military Nature
  • Treaties affecting the territorial integrity of the State or the fundamental rights and duties guaranteed by the SC
  • Treaties creating financial liabilities for the Public Treasury
  • Treaties involving amendments or repeal of laws or requiring legislative measures for their implementation[69]

D. Constitutional Amendment

The SC may be amended through two types of procedure, depending on the nature of the amendment.  The ordinary procedure may be used for a partial amendment not affecting matters related to fundamental rights and freedoms of the Spanish people.[70] I n this case, the amendment requires the vote of the majority of three-fifths of the members of each house.[71]  Once the amendment is adopted by the Cortes Generales, it must be ratified by referendum.[72]  In the case of total amendment, or where an amendment affects fundamental rights and freedoms of the Spanish people, the revision must be approved by a two-thirds majority of the members of each chamber, and the Cortes Generales is immediately dissolved.[73]  The newly elected chambers must ratify the decision and examine the new constitutional text, which will only be approved with a two-thirds majority vote in both houses.[74]  Once the amendment is approved, it must be submitted for ratification through referendum.[75]

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Prepared by Graciela Rodriguez-Ferrand
Senior Foreign Law Specialist
February 2018

[1] Constitución Espanola de 1978 [SC] [Spanish Constitution],‌documentos/ConstitucionINGLES.pdf, archived at

[2] Victor Ferreres Comella, The Constitution of Spain: A Contextual Analysis 18 (2013).

[3] Id.

[4] SC art. 1.2.

[5] Felipe González and Fernando Morán Sign Spain’s Treaty of Accession to the European Communities (Madrid, 12 June 1985),,‌_spain_s_treaty_of_accession_to_the_european_communities_madrid_12_june_1985-en-b80ade76-2844-4ef0-a4e8-7689e7f36c29.html (last visited Feb. 11, 2018).

[6] SC art. 137.

[7] Id. art. 2.

[8] Id. art. 66.

[9] Id. art. 68.

[10] Id. art. 69.

[11] Id. arts. 117–127.

[12] Id. arts. 1.3, 2, 137–158.

[13] Id. art. 141; Listado Standard de Provincias, Instituto Nacional de Estadística, (last visited Feb. 11, 2018), archived at

[14] SC art. 149.

[15] Id. art. 149.3.

[16] Id. art. 148.

[17] Id. art. 66.

[18] Las Cortes Generales, Senado de España (Feb. 25, 2016),‌temasclave/‌cortesgenerales/index.html, archived at

[19] SC art. 68.1.

[20] Id. arts. 68.4, 69.

[21] Id. arts. 66.3, 71.1.

[22] Id.

[23] Senado en el Sistema Bicameral Espanol, Senado de España (Feb. 26, 2016),‌web/conocersenado/temasclave/sistemabicameral/index.html, archived at

[24] SC art. 66.2.

[25] Id.

[26] Id.

[27] Id. art. 67.1.

[28] Id. art. 67.2; Ferreres Comella, supra note 2, at 101.

[29] SC art. 73.

[30] Id. art. 72.1.

[31] Id. art. 72.2.

[32] Id. art. 75.1.

[33] Id. art. 75.2.

[34] Id. art. 75.3.

[35] Id. art. 76.1.

[36] Id.

[37] Id. 76.2.

[38] Id. art. 68.1; Ferreres Comella, supra note2, at 95.

[39] SC art. 68.1.

[40] Id. art. 68.2.

[41] Id. 

[42] Id. art. 68.5.

[43] Id. art. 68.4.

[44] Elecciones generales 2016, Resultados del Congreso, El Pais,‌generales.html (last visited Feb. 12, 2018), archived at

[45] Id.

[46] SC. art. 69.2.

[47] Id.

[48] Id.

[49] Presencia de Mujeres en el Senado, Senado de España, Dec. 13, 2017,‌conocersenado/temasclave/presenciamujeres/index.html?lang=es_ES, archived at .

[50] SC art. 69.1.

[51] Composicion del Senado. Eleccion y Designacion de Senadores, Senado de España, July 19, 2016,, archived at

[52] Id.

[53] Id.

[54] Senadores en Activo. Distribucion por Grupos Parlamentarios, Senado de España, (last visited Feb. 13, 2018), archived at

[55] SC art. 89.1.

[56] Id. arts. 57, 59, 60.1.

[57] Id. art. 87.

[58] Id. art. 88.

[59] Id. art. 87.1.

[60] Id. art. 87.2.

[61] Id. art. 87.3.

[62] Id. art. 90.

[63] Id.

[64] Id. art. 81.1.

[65] Id. art. 81.2.

[66] Id. art. 91.

[67] Código Civil [Civil Code], Real Decreto de 24 de julio de 1889 por el que se publica el Código Civil art. 2.1, BOE, July 25, 1889,, archived at

[68] SC art. 94.2.

[69] Id. art. 94.

[70] Id. arts. 167, 168.

[71] Id. art. 167.

[72] Id. art. 167.3.

[73] Id. art. 168.1.

[74] Id. art. 168.2.

[75] Id. art. 168.3.

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Last Updated: 08/06/2019