Cantabria—Santander until 1982—is one of the 52 constituencies represented in the Congress of Deputies, the lower chamber of the Spanish parliament, the . The constituency (whose boundaries correspond to those of the homonymous province) currently elects five deputies. The electoral system uses the D'Hondt method and closed-list proportional voting, with a minimum threshold of three percent.

Electoral system The constituency was created as per the Political Reform Law and was first contested in the 1977 general election. The Law provided for the provinces of Spain to be established as multi-member districts in the Congress of Deputies,. with this regulation being maintained under the Spanish Constitution of 1978.. Additionally, the Constitution requires for any modification of the provincial limits to be approved under an organic law, needing an absolute majority in the Cortes Generales..

Voting is based on universal suffrage, comprising all Spanish nationals over 18 years of age with full political rights, provided that they have not been deprived of the right to vote by a final sentence.. The only exception was in 1977, when this was limited to nationals over 21 years of age and in full enjoyment of their political and civil rights.; . Amendments in 2011 required non-resident citizens to apply for voting, a system known as "begged" voting ().. which was abolished in 2022. Further, amendments in 2018 granted the right to vote to those legally incapacitated. The Congress of Deputies has a minimum of 300 and a maximum of 400 seats, with electoral provisions fixing its size at 350. Of these, 348 are elected in 50 multi-member constituencies corresponding to the provinces of Spain—each of which is 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 are allocated to Ceuta and Melilla as single-member districts elected by plurality voting.; ; ; . The use of this electoral method may result in a higher effective threshold depending on district magnitude and vote distribution. The law does not provide for by-elections to fill vacant seats; instead, any vacancies arising after the proclamation of candidates and during the legislative term are filled by the next candidates on the party lists or, when required, by designated substitutes.; .

The electoral law allows for parties and federations registered in the interior ministry, alliances and groupings of electors to present lists of candidates. Parties and federations intending to form an alliance are required to inform the relevant electoral commission within 10 days of the election call—15 before 1985—whereas groupings of electors need to secure the signature of at least one percent of the electorate in the constituencies for which they seek election—one permille of the electorate, with a compulsory minimum of 500 signatures, until 1985—disallowing electors from signing for more than one list. Also since 2011, parties, federations or alliances that have not obtained a mandate in either chamber of the at the preceding election are required to secure the signature of at least 0.1 percent of electors in the aforementioned constituencies.; . Amendments in 2007 required a balanced composition of men and women in the electoral lists, so that candidates of either sex made up at least 40 percent of the total composition; further amendments in 2024 required the use of a zipper system..

Deputies Deputies 1977–present Legislature Election Distribution Constituent 1977 1 3 1 1st 1979 2 3 2nd 1982 3 2 3rd 1986 3 2 4th 1989 3 2 5th 1993 3 2 6th 1996 2 3 7th 2000 2 3 8th 2004 2 3 9th 2008 2 3 10th 2011 1 4 11th 2015 1 1 1 2 12th 2016 1 1 1 2 13th 2019 (Apr) 2 1 1 1 14th 2019 (Nov) 1 1 2 1 15th 2023 2 2 1

General elections 2023 + Summary of the 23 July 2023 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 147,326 42.08 +16.22 2 ±0 Spanish Socialist Workers' Party (PSOE) 116,596 33.30 +10.06 2 +1 Vox (Vox) 49,243 14.06 –0.87 1 ±0 Unite (Sumar)1 29,713 8.49 –0.19 0 ±0 Animalist Party with the Environment (PACMA)2 2,089 0.60 +0.03 0 ±0 Workers' Front (FO) 790 0.23 New 0 ±0 Communist Party of the Workers of Spain (PCTE) 598 0.17 +0.09 0 ±0 Zero Cuts (Recortes Cero) 533 0.15 +0.08 0 ±0 Regionalist Party of Cantabria (PRC) n/a n/a –21.04 0 –1 Blank ballots 3,262 0.93 +0.42 Total 350,150 5 ±0 Valid votes 350,150 98.59 –0.58 Invalid votes 4,995 1.41 +0.58 Votes cast / turnout 355,145 69.94 +4.20 Abstentions 152,673 30.06 –4.20 Registered voters 507,818 Sources

November 2019 + Summary of the 10 November 2019 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 84,583 25.86 +4.17 2 +1 Spanish Socialist Workers' Party (PSOE) 76,028 23.24 –1.97 1 –1 Regionalist Party of Cantabria (PRC) 68,830 21.04 +6.49 1 ±0 Vox (Vox) 48,827 14.93 +3.75 1 +1 United We Can (Podemos–IU) 28,376 8.68 –1.56 0 ±0 Citizens–Party of the Citizenry (Cs) 15,609 4.77 –10.37 0 –1 Animalist Party Against Mistreatment of Animals (PACMA) 1,856 0.57 –0.28 0 ±0 Communist Party of the Peoples of Spain (PCPE) 262 0.08 ±0.00 0 ±0 Blank Seats (EB) 259 0.08 –0.04 0 ±0 Communist Party of the Workers of Spain (PCTE) 247 0.08 +0.01 0 ±0 Zero Cuts–Green Group (Recortes Cero–GV) 232 0.07 –0.02 0 ±0 For a Fairer World (PUM+J) 187 0.06 –0.02 0 ±0 Libertarian Party (P–LIB) 126 0.04 –0.01 0 ±0 Blank ballots 1,667 0.51 –0.13 Total 327,089 5 ±0 Valid votes 327,089 99.17 +0.22 Invalid votes 2,732 0.83 –0.22 Votes cast / turnout 329,821 65.74 –6.64 Abstentions 171,855 34.26 +6.64 Registered voters 501,676 Sources

April 2019 + Summary of the 28 April 2019 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− Spanish Socialist Workers' Party (PSOE) 90,534 25.21 +1.69 2 +1 People's Party (PP) 77,902 21.69 –19.86 1 –1 Citizens–Party of the Citizenry (Cs) 54,361 15.14 +0.74 1 ±0 Regionalist Party of Cantabria (PRC) 52,266 14.55 New 1 +1 Vox (Vox) 40,139 11.18 +10.97 0 ±0 United We Can (Podemos–IU–Equo) 36,784 10.24 –7.49 0 –1 Animalist Party Against Mistreatment of Animals (PACMA) 3,049 0.85 –0.15 0 ±0 Blank Seats (EB) 427 0.12 –0.06 0 ±0 Zero Cuts–Green Group (Recortes Cero–GV) 332 0.09 –0.05 0 ±0 Communist Party of the Peoples of Spain (PCPE) 286 0.08 –0.06 0 ±0 For a Fairer World (PUM+J) 274 0.08 New 0 ±0 Communist Party of the Workers of Spain (PCTE) 260 0.07 New 0 ±0 Libertarian Party (P–LIB) 187 0.05 +0.01 0 ±0 Blank ballots 2,303 0.64 –0.09 Total 359,104 5 ±0 Valid votes 359,104 98.95 +0.06 Invalid votes 3,806 1.05 –0.06 Votes cast / turnout 362,910 72.38 +3.86 Abstentions 138,501 27.62 –3.86 Registered voters 501,411 Sources

2016 + Summary of the 26 June 2016 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 140,252 41.55 +4.64 2 ±0 Spanish Socialist Workers' Party (PSOE) 79,407 23.52 +1.11 1 ±0 United We Can (Podemos–IU–Equo)1 59,845 17.73 –4.56 1 ±0 Citizens–Party of the Citizenry (C's) 48,626 14.40 –0.85 1 ±0 Animalist Party Against Mistreatment of Animals (PACMA) 3,369 1.00 +0.16 0 ±0 Union, Progress and Democracy (UPyD) 1,051 0.31 –0.51 0 ±0 Vox (Vox) 713 0.21 –0.05 0 ±0 Blank Seats (EB) 596 0.18 New 0 ±0 Zero Cuts–Green Group (Recortes Cero–GV) 483 0.14 –0.01 0 ±0 Communist Party of the Peoples of Spain (PCPE) 468 0.14 +0.01 0 ±0 Internationalist Solidarity and Self-Management (SAIn) 156 0.05 ±0.00 0 ±0 Libertarian Party (P–LIB) 147 0.04 New 0 ±0 Blank ballots 2,454 0.73 –0.08 Total 337,567 5 ±0 Valid votes 337,567 98.89 –0.01 Invalid votes 3,781 1.11 +0.01 Votes cast / turnout 341,348 68.52 –2.45 Abstentions 156,855 31.48 +2.45 Registered voters 498,203 Sources

2015 + Summary of the 20 December 2015 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 129,216 36.91 –15.26 2 –2 Spanish Socialist Workers' Party (PSOE) 78,460 22.41 –2.82 1 ±0 We Can (Podemos) 62,569 17.87 New 1 +1 Citizens–Party of the Citizenry (C's) 53,371 15.25 New 1 +1 United Left–Popular Unity in Common (IU–UPeC) 15,488 4.42 +0.83 0 ±0 Animalist Party Against Mistreatment of Animals (PACMA) 2,943 0.84 +0.49 0 ±0 Union, Progress and Democracy (UPyD) 2,875 0.82 –2.77 0 ±0 Vox (Vox) 901 0.26 New 0 ±0 Zero Cuts–Green Group (Recortes Cero–GV) 529 0.15 New 0 ±0 Communist Party of the Peoples of Spain (PCPE) 461 0.13 –0.03 0 ±0 Humanist Party (PH) 236 0.07 –0.01 0 ±0 Internationalist Solidarity and Self-Management (SAIn) 173 0.05 –0.03 0 ±0 Blank ballots 2,849 0.81 –0.37 Total 350,071 5 ±0 Valid votes 350,071 98.90 +0.04 Invalid votes 3,904 1.10 –0.04 Votes cast / turnout 353,975 70.97 –0.59 Abstentions 144,796 29.03 +0.59 Registered voters 498,771 Sources

2011 + Summary of the 20 November 2011 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 183,244 52.17 +2.18 4 +1 Spanish Socialist Workers' Party (PSOE) 88,624 25.23 –18.38 1 –1 Regionalist Party of Cantabria (PRC) 44,010 12.53 New 0 ±0 Union, Progress and Democracy (UPyD) 12,614 3.59 +2.21 0 ±0 United Left of Cantabria: Plural Left (IUC) 12,608 3.59 +1.32 0 ±0 Equo (Equo) 2,482 0.71 New 0 ±0 Animalist Party Against Mistreatment of Animals (PACMA) 1,232 0.35 +0.16 0 ±0 Communist Party of the Peoples of Spain (PCPE) 578 0.16 +0.03 0 ±0 Enough is Enough, Open Grouping of Political Parties (Basta Ya) 380 0.11 New 0 ±0 Anti-capitalists (Anticapitalistas) 354 0.10 New 0 ±0 Republicans (RPS) 277 0.08 New 0 ±0 Humanist Party (PH) 275 0.08 +0.03 0 ±0 Internationalist Solidarity and Self-Management (SAIn) 269 0.08 +0.02 0 ±0 Communist Unification of Spain (UCE) 145 0.04 New 0 ±0 Blank ballots 4,157 1.18 –0.05 Total 351,249 5 ±0 Valid votes 351,249 98.86 –0.35 Invalid votes 4,040 1.14 +0.35 Votes cast / turnout 355,289 71.56 –4.82 Abstentions 141,194 28.44 +4.82 Registered voters 496,483 Sources

2008 + Summary of the 9 March 2008 Congress of Deputies election results in Cantabria Parties and alliances Popular vote Seats Votes % ±pp Total +/− People's Party (PP) 184,853 49.99 –1.91 3 ±0 Spanish Socialist Workers' Party (PSOE) 161,279 43.61 +2.74 2 ±0 United Left (IU) 8,395 2.27 –1.04 0 ±0 Union, Progress and Democracy (UPyD) 5,094 1.38 New 0 ±0 The Greens of Europe (LVdE) 1,060 0.29 New 0 ±0 Anti-Bullfighting Party Against Mistreatment of Animals (PACMA) 713 0.19 New 0 ±0 Communist Party of the Peoples of Spain (PCPE) 497 0.13 +0.01 0 ±0 Social Democratic Party (PSD) 444 0.12 New 0 ±0 Engine and Sports Alternative (AMD) 394 0.11 New 0 ±0 For a Fairer World (PUM+J) 353 0.10 New 0 ±0 Alternative in Blank (ABLA) 305 0.08 New 0 ±0 Spanish Phalanx of the CNSO (FE de las JONS) 302 0.08 +0.02 0 ±0 Citizens for Blank Votes (CenB) 297 0.08 –0.28 0 ±0 Citizens–Party of the Citizenry (C's) 286 0.08 New 0 ±0 Internationalist Solidarity and Self-Management (SAIn) 219 0.06 New 0 ±0 Humanist Party (PH) 175 0.05 –0.14 0 ±0 Family and Life Party (PFyV) 166 0.04 New 0 ±0 Spanish Alternative (AES) 157 0.04 New 0 ±0 National Democracy (DN) 154 0.04 –0.02 0 ±0 Authentic Phalanx (FA) 112 0.03 –0.01 0 ±0 Blank ballots 4,551 1.23 –1.02 Total 369,806 5 ±0 Valid votes 369,806 99.21 +0.09 Invalid votes 2,926 0.79 –0.09 Votes cast / turnout 372,732 76.38 –0.85 Abstentions 115,277 23.62 +0.85 Registered voters 488,009 Sources

2004