Soria is one of the nine constituencies (Spanish: circunscripciones) represented in the Cortes of Castile and León, the regional legislature of the Autonomous Community of Castile and León. The constituency currently elects five deputies. Its boundaries correspond to those of the Spanish province of Soria. The electoral system uses the D'Hondt method and a closed-list proportional representation, with a minimum threshold of three percent.

The constituency was created as per the Statute of Autonomy of Castile and León of 1983 and was first contested in the 1983 regional election. The Statute provided for the nine provinces in Castile and León—Ávila, Burgos, León, Palencia, Salamanca, Segovia, Soria, Valladolid and Zamora—to be established as multi-member districts in the Cortes of Castile and León, with this regulation being maintained under the 1987 regional electoral law. Each constituency is entitled to an initial minimum of three seats, with one additional member per each 45,000 inhabitants or fraction greater than 22,500.

Voting is on the basis of universal suffrage, which comprises all nationals over eighteen, registered in Castile and León and in full enjoyment of their political rights. Amendments to the electoral law in 2011 required for Castilian-Leonese people abroad to apply for voting before being permitted to vote, a system known as "begged" or expat vote (Spanish: Voto rogado) which was abolished in 2022. Seats are elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which includes blank ballots—being applied in each constituency. The use of the D'Hondt method might result in a higher effective threshold, depending on the district magnitude.

The electoral law allows for parties and federations registered in the interior ministry, coalitions and groupings of electors to present lists of candidates. Parties and federations intending to form a coalition ahead of an election are required to inform the relevant Electoral Commission within ten days of the election call—fifteen 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-thousandth of the electorate, with a compulsory minimum of 500 signatures, until 1985—disallowing electors from signing for more than one list of candidates.

Procurators 1983–present
Key to parties   PSOE   SY   CDS   PP   CP   AP
Cortes	Election	Distribution
1st	1983	2 3
2nd	1987	2 1 2
3rd	1991	2 3
4th	1995	1 4
5th	1999	2 3
6th	2003	2 3
7th	2007	2 3
8th	2011	2 3
9th	2015	2 3
10th	2019	3 2
11th	2022	1 3 1

Summary of the 13 February 2022 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	Soria Now! (SY)	19,385	42.72	New	3	+3
	People's Party (PP)	10,822	23.85	–3.77	1	–1
	Spanish Socialist Workers' Party (PSOE)	8,193	18.06	–22.67	1	–2
	Vox (Vox)	5,204	11.47	+7.20	0	±0
	United We Can Castile and León (Podemos–IU–AV)	1,020	2.25	–4.00	0	±0
	Citizens–Party of the Citizenry (Cs)	351	0.77	–10.50	0	±0
	Animalist Party Against Mistreatment of Animals (PACMA)	89	0.20	–0.30	0	±0
	Castilian Party–Commoners' Land–Zero Cuts (PCAS–TC–RC)	41	0.09	New	0	±0
	Progress Party of Castile and León Cities (PPCCAL)	23	0.05	New	0	±0
	For a Fairer World (PUM+J)	13	0.03	New	0	±0
Blank ballots		232	0.51	–0.84
Total		45,373			5	±0
Valid votes		45,373	99.48	+0.54
Invalid votes		239	0.52	–0.54
Votes cast / turnout		45,612	59.81	–4.12
Abstentions		30,645	40.19	+4.12
Registered voters		76,257
Sources
Footnotes: United We Can Castile and León results are compared to the combined totals of We Can–Equo and United Left–Anticapitalists in the 2019 election.

Summary of the 26 May 2019 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	Spanish Socialist Workers' Party (PSOE)	19,794	40.73	+9.56	3	+1
	People's Party (PP)	13,423	27.62	–9.23	2	–1
	Citizens–Party of the Citizenry (Cs)	5,476	11.27	–0.87	0	±0
	Sorian People's Platform (PPSO)	3,895	8.01	New	0	±0
	We Can–Equo (Podemos–Equo)	2,464	5.07	–6.94	0	±0
	Vox (Vox)	2,075	4.27	New	0	±0
	United Left–Anticapitalists (IU–Anticapitalistas–PCAS/TC–ALTER)	575	1.18	–2.23	0	±0
	Animalist Party Against Mistreatment of Animals (PACMA)	244	0.50	New	0	±0
Blank ballots		657	1.35	–2.12
Total		48,603			5	±0
Valid votes		48,603	98.94	+1.44
Invalid votes		519	1.06	–1.44
Votes cast / turnout		49,122	63.93	+0.19
Abstentions		27,716	36.07	–0.19
Registered voters		76,838
Sources
Footnotes: United Left–Anticapitalists results are compared to the combined totals of United Left–Equo: Convergence for Castile and León and Castilian Party–Commoners' Land: Pact in the 2015 election. Regionalist Union of Castile and León results are compared to Regionalist Democracy of Castile and León totals in the 2015 election. Democratic Centre Coalition results are compared to Independent Candidacy–Citizens of Democratic Centre totals in the 2015 election.

Summary of the 24 May 2015 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	17,712	36.85	–15.16	3	±0
	Spanish Socialist Workers' Party (PSOE)	14,978	31.17	–1.76	2	±0
	Citizens–Party of the Citizenry (C's)	5,834	12.14	New	0	±0
	We Can (Podemos)	5,772	12.01	New	0	±0
	United Left–Equo: Convergence for Castile and León (IU–Equo)	1,368	2.85	–0.25	0	±0
	Union, Progress and Democracy (UPyD)	460	0.96	New	0	±0
	Castilian Party–Commoners' Land: Pact (PCAS–TC–Pacto)	270	0.56	–0.08	0	±0
Blank ballots		1,666	3.47	–1.66
Total		48,060			5	±0
Valid votes		48,060	97.50	–0.20
Invalid votes		1,234	2.50	+0.20
Votes cast / turnout		49,294	63.74	–3.20
Abstentions		28,042	36.26	+3.20
Registered voters		77,336
Sources

Summary of the 22 May 2011 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	26,264	52.01	+1.64	3	±0
	Spanish Socialist Workers' Party (PSOE)	16,630	32.93	–3.76	2	±0
	Initiative for the Development of Soria (IDES)	2,680	5.31	–1.68	0	±0
	United Left of Castile and León (IUCyL)	1,565	3.10	+1.40	0	±0
	Party of Castile and León (PCAL)	323	0.64	+0.20	0	±0
	Anti-Bullfighting Party Against Mistreatment of Animals (PACMA)	256	0.51	New	0	±0
	Communist Unification of Spain (UCE)	187	0.37	New	0	±0
Blank ballots		2,590	5.13	+2.36
Total		50,495			5	±0
Valid votes		50,495	97.70	–1.26
Invalid votes		1,189	2.30	+1.26
Votes cast / turnout		51,684	66.94	–3.05
Abstentions		25,523	33.06	+3.05
Registered voters		77,207
Sources
Footnotes: Party of Castile and León results are compared to Commoners' Land–Alternative for Castile and León totals in the 2007 election.

Summary of the 27 May 2007 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	27,078	50.37	–3.00	3	±0
	Spanish Socialist Workers' Party (PSOE)	19,727	36.69	+0.07	2	±0
	Initiative for the Development of Soria (IDES)	3,760	6.99	+3.54	0	±0
	United Left–The Greens–Commitment for Castile and León (IU–LV–CyL)	912	1.70	–0.39	0	±0
	The Greens (LV)	352	0.65	New	0	±0
	Commoners' Land–Alternative for Castile and León (TC–ACAL)	235	0.44	–0.11	0	±0
	Republican Left (IR)	209	0.39	+0.10	0	±0
Blank ballots		1,489	2.77	–0.60
Total		53,762			5	±0
Valid votes		53,762	98.96	+0.19
Invalid votes		565	1.04	–0.19
Votes cast / turnout		54,327	69.99	–1.54
Abstentions		23,289	30.01	+1.54
Registered voters		77,616
Sources
Footnotes: Leonese People's Union–United Zamora results are compared to the combined totals of Leonese People's Union and United Zamora in the 2003 election. Aggregated data for Commoners' Land and Party of El Bierzo. The Greens results are compared to the combined totals of The Greens–Left Forum, The Greens and The Greens–Cives in the 2003 election. Spanish Phalanx of the CNSO results are compared to Independent Spanish Phalanx–Phalanx 2000 totals in the 2003 election.

Summary of the 25 May 2003 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	29,534	53.37	–3.33	3	±0
	Spanish Socialist Workers' Party (PSOE)	20,265	36.62	+4.56	2	±0
	Initiative for the Development of Soria (IDES)	1,908	3.45	New	0	±0
	United Left of Castile and León (IUCyL)	1,155	2.09	–3.74	0	±0
	Commoners' Land–Castilian Nationalist Party (TC–PNC)	306	0.55	–0.29	0	±0
	Republican Left (IR)	162	0.29	New	0	±0
	Castilian Left (IzCa)	142	0.26	New	0	±0
Blank ballots		1,864	3.37	–0.50
Total		55,336			5	±0
Valid votes		55,336	98.77	+0.10
Invalid votes		689	1.23	–0.10
Votes cast / turnout		56,025	71.53	+7.14
Abstentions		22,304	28.47	–7.14
Registered voters		78,329
Sources

Summary of the 13 June 1999 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	28,701	56.70	–2.51	3	–1
	Spanish Socialist Workers' Party (PSOE)	16,227	32.06	+3.71	2	+1
	United Left of Castile and León (IUCyL)	2,949	5.83	–2.33	0	±0
	Commoners' Land–Castilian Nationalist Party (TC–PNC)	424	0.84	+0.35	0	±0
	Regionalist Unity of Castile and León (URCL)	362	0.72	New	0	±0
Blank ballots		1,957	3.87	+1.05
Total		50,620			5	±0
Valid votes		50,620	98.67	–0.16
Invalid votes		684	1.33	+0.16
Votes cast / turnout		51,304	64.39	–4.96
Abstentions		28,373	35.61	+4.96
Registered voters		79,677
Sources

Summary of the 28 May 1995 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	32,089	59.21	+6.94	4	+1
	Spanish Socialist Workers' Party (PSOE)	15,361	28.35	–5.54	1	–1
	United Left of Castile and León (IU)	4,422	8.16	+5.48	0	±0
	Sorian Progressive Union (US)	417	0.77	New	0	±0
	Commoners' Land–Castilian Nationalist Party (TC–PNC)	264	0.49	+0.10	0	±0
	Party of El Bierzo (PB)	110	0.20	New	0	±0
Blank ballots		1,529	2.82	+1.04
Total		54,192			5	±0
Valid votes		54,192	98.83	–0.45
Invalid votes		643	1.17	+0.45
Votes cast / turnout		54,835	69.35	+3.97
Abstentions		24,235	30.65	–3.97
Registered voters		79,070
Sources

Summary of the 26 May 1991 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Party (PP)	26,977	52.27	+5.03	3	+1
	Spanish Socialist Workers' Party (PSOE)	17,492	33.89	+1.55	2	±0
	Democratic and Social Centre (CDS)	3,302	6.40	–7.94	0	–1
	United Left (IU)	1,385	2.68	±0.00	0	±0
	Castilianist Union (UC)	528	1.02	New	0	±0
	The Greens (LV)	511	0.99	New	0	±0
	Nationalist Party of Castile and León (PANCAL)	298	0.58	–0.14	0	±0
	Commoners' Land (TC)	201	0.39	New	0	±0
Blank ballots		917	1.78	–0.21
Total		51,611			5	±0
Valid votes		51,611	99.28	+2.10
Invalid votes		373	0.72	–2.10
Votes cast / turnout		51,984	65.38	–5.51
Abstentions		27,529	34.62	+5.51
Registered voters		79,513
Sources
Footnotes: People's Party results are compared to the combined totals of People's Alliance and People's Democratic Party in the 1987 election.

Summary of the 10 June 1987 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Alliance (AP)	22,668	41.75	–2.48	2	–1
	Spanish Socialist Workers' Party (PSOE)	17,562	32.34	–6.21	2	±0
	Democratic and Social Centre (CDS)	7,786	14.34	+6.62	1	+1
	People's Democratic Party (PDP)	2,981	5.49	New	0	±0
	United Left (IU)	1,454	2.68	+0.70	0	±0
	Nationalist Party of Castile and León (PNCL–PANCAL)	391	0.72	New	0	±0
	Workers' Party of Spain–Communist Unity (PTE–UC)	265	0.49	New	0	±0
	Leonesist Union (UNLE)	116	0.21	New	0	±0
Blank ballots		1,078	1.99	+0.80
Total		54,301			5	±0
Valid votes		54,301	97.18	–0.72
Invalid votes		1,576	2.82	+0.72
Votes cast / turnout		55,877	70.89	+3.54
Abstentions		22,950	29.11	–3.54
Registered voters		78,827
Sources
Footnotes: People's Alliance results are compared to People's Coalition totals in the 1983 election. United Left results are compared to Communist Party of Spain totals in the 1983 election.

Summary of the 8 May 1983 Cortes of Castile and León election results in Soria

Parties and alliances		Popular vote			Seats
		Votes	%	±pp	Total	+/−
	People's Coalition (AP–PDP–UL)	23,487	44.23	n/a	3	n/a
	Spanish Socialist Workers' Party (PSOE)	20,470	38.55	n/a	2	n/a
	Democratic and Social Centre (CDS)	4,098	7.72	n/a	0	n/a
	Agrarian Bloc–Regionalist Party of the Leonese Country (BAR–PREPAL)	3,359	6.33	n/a	0	n/a
	Communist Party of Castile and León (PCCL–PCE)	1,054	1.98	n/a	0	n/a
Blank ballots		632	1.19	n/a
Total		53,100			5	n/a
Valid votes		53,100	97.90	n/a
Invalid votes		1,138	2.10	n/a
Votes cast / turnout		54,238	67.35	n/a
Abstentions		26,290	32.65	n/a
Registered voters		80,528
Sources

41°40′N 2°40′W / 41.667°N 2.667°W / 41.667; -2.667