Södermanland County () is one of the 29 multi-member constituencies of the Riksdag, the national legislature of Sweden. The constituency was established in 1970 when the Riksdag changed from a bicameral legislature to a unicameral legislature. It is conterminous with the county of Södermanland. The constituency currently elects nine of the 349 members of the Riksdag using the open party-list proportional representation electoral system. At the 2022 general election it had 223,767 registered electors.

Electoral system Södermanland County currently elects nine of the 349 members of the Riksdag using the open party-list proportional representation electoral system. Constituency seats are allocated using the modified Sainte-Laguë method. Only parties that reach the 4% national threshold and parties that receive at least 12% of the vote in the constituency compete for constituency seats. Supplementary levelling seats may also be allocated at the constituency level to parties that reach the 4% national threshold.

Prior to 1997 voters could cast any ballot paper they wanted though it had to contain the name of a party and the name of at least one candidate nominated by that party in the constituency. It was common for parties to hand out ballot papers with their name and list of candidates at the entrance of polling stations. Voters could delete the names of candidates or write-in the names of other candidates but in practice these options weren't used enough by voters to have any significant impact on the results and consequently elections operated as a closed system.

Since 1997, elections in Sweden follow the French model in having separate ballot papers for each party/list in a constituency. There are two ballot papers for each party - a party ballot paper () with just the name of the party and a name ballot paper () with the name of the party and its list of candidates. There are also blank ballot papers (). Voters can initially pick as many ballot papers as they wish and then, in the secrecy of the voting booth, they select a single ballot paper of their choice. If they chose a name ballot paper they have the option of casting a preferential vote for one of their chosen party's candidates. If they chose a blank ballot paper they can write the name of any party including unregistered parties and, optionally, they can write the name of any person as their preferred candidate, even one that does not belong to their chosen party. They then place their chosen ballot paper in an envelope which is placed in the ballot box, discarding all other ballot papers they picked.

Seats won by each party/list in a constituency are allocated to its candidates in order of preference votes (a personal mandate), provided that the candidate has received at least 8% of votes cast for their party in the constituency (5% since January 2011). Any unfilled seats are then allocated to the party's remaining candidates in the order they appear on the party list (a party mandate).

Election results Summary Election LeftV / VPK SocialDemocratsS GreensMP CentreC LiberalsL / FP / F ModeratesM ChristianDemocratsKD / KDS SwedenDemocratsSD colspan=3 colspan=3 colspan=3 colspan=3 colspan=3 colspan=3 colspan=3 colspan=3 Votes % Seats Votes % Seats Votes % Seats Votes % Seats Votes % Seats Votes % Seats Votes % Seats Votes % Seats2022 9,605 5.20% 0 60,891 32.94% 4 7,409 4.01% 0 10,989 5.94% 1 6,643 3.59% 0 35,513 19.21% 2 8,772 4.74% 0 42,547 23.01% 22018 12,162 6.63% 1 57,612 31.40% 3 6,773 3.69% 0 13,577 7.40% 1 7,958 4.34% 0 37,401 20.39% 2 10,089 5.50% 0 35,450 19.32% 22014 9,084 5.09% 0 61,834 34.62% 4 11,165 6.25% 0 9,774 5.47% 0 7,776 4.35% 0 39,991 22.39% 3 6,888 3.86% 0 26,887 15.05% 22010 8,637 5.04% 0 59,463 34.69% 4 13,065 7.62% 1 9,850 5.75% 0 11,299 6.59% 0 47,889 27.94% 3 8,095 4.72% 0 11,370 6.63% 12006 7,830 4.90% 0 67,458 42.23% 5 8,218 5.14% 0 10,942 6.85% 1 10,843 6.79% 1 37,350 23.38% 2 9,950 6.23% 0 4,050 2.54% 02002 10,862 7.13% 1 72,092 47.29% 5 7,346 4.82% 0 8,377 5.50% 0 18,104 11.88% 1 20,000 13.12% 1 12,655 8.30% 1 1,478 0.97% 01998 16,528 10.84% 1 66,147 43.38% 5 7,436 4.88% 0 7,330 4.81% 0 6,265 4.11% 0 29,499 19.35% 2 16,657 10.92% 1 1994 8,829 5.37% 0 84,976 51.73% 5 8,280 5.04% 0 10,940 6.66% 1 11,177 6.80% 1 31,061 18.91% 2 5,579 3.40% 0 1991 6,093 3.76% 0 71,285 43.99% 4 4,777 2.95% 0 12,903 7.96% 1 14,587 9.00% 1 29,722 18.34% 2 9,970 6.15% 0 1988 7,673 4.81% 0 79,234 49.67% 5 8,139 5.10% 0 16,014 10.04% 1 19,209 12.04% 1 24,342 15.26% 2 3,816 2.39% 0 1985 6,942 4.18% 0 85,681 51.56% 5 2,567 1.54% 0 18,131 10.91% 1 22,315 13.43% 1 29,905 18.00% 2 with C 1982 6,839 4.10% 0 88,077 52.82% 6 2,807 1.68% 0 23,476 14.08% 1 9,758 5.85% 0 32,742 19.64% 2 2,741 1.64% 0 1979 6,399 3.91% 0 83,340 50.90% 5 26,867 16.41% 2 17,478 10.67% 1 26,616 16.25% 1 2,153 1.31% 0 1976 5,058 3.10% 0 81,178 49.76% 5 36,114 22.14% 2 17,577 10.77% 1 20,419 12.52% 1 2,286 1.40% 0 1973 5,795 3.75% 0 78,498 50.73% 5 35,658 23.05% 2 14,242 9.20% 1 17,127 11.07% 1 2,831 1.83% 0 1970 4,791 3.20% 0 79,586 53.10% 5 26,749 17.85% 2 22,140 14.77% 1 13,709 9.15% 1 2,650 1.77% 0 (Excludes levelling seats. Figures in italics represent alliances/joint lists.)

Detailed

2020s 2022 Results of the 2022 general election held on 11 September 2022:

Party Votes per municipality Totalvotes % SeatsEskils-tuna Flen Gnesta Katrine-holm Ny-köping Oxelö-sund Sträng-näs Trosa Vingå-ker Swedish Social Democratic Party S 20,584 3,428 2,141 8,059 12,623 2,923 6,541 2,637 1,955 60,891 32.94% 4 0 4 Sweden Democrats SD 15,090 2,452 1,631 4,645 7,466 1,685 5,626 2,253 1,699 42,547 23.01% 2 0 2 Moderate Party M 11,505 1,506 1,428 3,597 7,129 1,270 5,722 2,365 991 35,513 19.21% 2 0 2 Centre Party C 3,180 616 557 1,302 2,521 276 1,607 632 298 10,989 5.94% 1 0 1 Left Party V 3,695 506 505 1,001 1,832 515 961 326 264 9,605 5.20% 0 1 1 Christian Democrats KD 2,949 499 319 997 1,776 251 1,188 484 309 8,772 4.74% 0 0 0 Green Party MP 2,158 404 456 795 1,734 215 998 454 195 7,409 4.01% 0 1 1 Liberals L 2,245 302 217 646 1,422 191 1,097 397 126 6,643 3.59% 0 0 0 Nuance Party PNy 356 33 5 57 153 48 57 8 12 729 0.39% 0 0 0 Alternative for Sweden AfS 154 22 25 64 74 37 90 20 22 508 0.27% 0 0 0 Citizens' Coalition MED 122 16 19 25 49 9 44 19 6 309 0.17% 0 0 0 Pirate Party PP 57 4 5 35 27 20 43 10 3 204 0.11% 0 0 0 The Push Buttons Kn 42 7 3 18 29 9 18 10 8 144 0.08% 0 0 0 Human Rights and Democracy MoD 31 9 20 12 32 3 12 19 1 139 0.08% 0 0 0 Christian Values Party KrVP 50 14 1 20 28 14 4 4 3 138 0.07% 0 0 0 Feminist Initiative FI 30 2 10 8 15 5 10 2 5 87 0.05% 0 0 0 Unity ENH 11 1 6 2 16 3 10 0 1 50 0.03% 0 0 0 Direct Democrats DD 18 0 1 4 14 7 4 1 49 0.03% 0 0 0 Independent Rural Party LPo 4 12 3 2 6 2 10 1 0 40 0.02% 0 0 0 Climate Alliance KA 6 0 2 4 11 4 1 0 0 28 0.02% 0 0 0 Nordic Resistance Movement NMR 10 2 2 5 5 1 1 0 1 27 0.01% 0 0 0 Communist Party of Sweden SKP 5 0 1 8 0 3 3 0 0 20 0.01% 0 0 0 Turning Point Party PV 2 0 1 4 2 0 0 1 0 10 0.01% 0 0 0 Classical Liberal Party KLP 2 0 0 1 2 0 1 2 0 8 0.00% 0 0 0 Socialist Welfare Party S-V 4 0 0 0 1 0 0 0 0 5 0.00% 0 0 0 Basic Income Party BASIP 0 1 0 0 1 0 2 0 0 4 0.00% 0 0 0 Hard Line Sweden 1 0 1 0 0 0 0 0 1 3 0.00% 0 0 0 Donald Duck Party 1 0 0 0 0 0 0 0 0 1 0.00% 0 0 0 European Workers Party EAP 0 0 1 0 0 0 0 0 0 1 0.00% 0 0 0 Free Choice 0 0 0 0 0 0 0 1 0 1 0.00% 0 0 0 John Mikkonen 0 0 0 0 0 0 0 1 0 1 0.00% 0 0 0 New Democracy 0 0 0 1 0 0 0 0 0 1 0.00% 0 0 0 Political Shift 0 1 0 0 0 0 0 0 0 1 0.00% 0 0 0 Positive Community Initiative PSI 0 0 0 1 0 0 0 0 0 1 0.00% 0 0 0 Referendum Party 1 0 0 0 0 0 0 0 0 1 0.00% 0 0 0 Scania Party SKÅ 0 0 0 1 0 0 0 0 0 1 0.00% 0 0 0Valid votes 62,313 9,837 7,360 21,314 36,968 7,484 24,053 9,650 5,901 184,880 100.00% 9 2 11Blank votes 643 95 82 212 366 53 233 86 56 1,826 0.98% Rejected votes – unregistered parties 13 2 1 3 7 0 1 2 4 33 0.02% Rejected votes – other 49 5 4 21 26 4 22 6 5 142 0.08% Total polled 63,018 9,939 7,447 21,550 37,367 7,541 24,309 9,744 5,966 186,881 83.52% Registered electors 78,420 12,039 8,615 25,962 43,569 9,072 28,212 11,006 6,872 223,767 Turnout 80.36% 82.56% 86.44% 83.01% 85.77% 83.12% 86.17% 88.53% 86.82% 83.52%

The following candidates were elected: Constituency seats (personal mandates) - Ulf Kristersson (M), 7,331 votes. Constituency seats (party mandates) - Sofia Amloh (S), 1,626 votes; Hans Ekström (S), 964 votes; Mattias Eriksson Falk (SD), 1 vote; Caroline Helmersson Olsson (S), 537 votes; Martina Johansson (C), 450 votes; Ann-Sofie Lifvenhage (M), 433 votes; Adam Marttinen (SD), 196 votes; and Fredrik Olovsson (S), 1,386 votes. Levelling seats (personal mandates) - Linus Lakso (MP), 443 votes. Levelling seats (party mandates) - Lotta Johnsson Fornarve (V), 404 votes.

2010s 2018 Results of the 2018 general election held on 9 September 2018:

Party Votes per municipality Totalvotes % SeatsEskils-tuna Flen Gnesta Katrine-holm Ny-köping Oxelö-sund Sträng-näs Trosa Vingå-ker Swedish Social Democratic Party S 20,210 3,338 1,862 8,054 11,724 2,993 5,384 2,073 1,974 57,612 31.40% 3 0 3 Moderate Party M 12,488 1,706 1,456 3,745 7,368 1,199 6,102 2,407 930 37,401 20.39% 2 0 2 Sweden Democrats SD 13,140 2,150 1,356 3,841 5,912 1,419 4,526 1,666 1,440 35,450 19.32% 2 0 2 Centre Party C 3,713 840 774 1,730 3,133 320 1,837 814 416 13,577 7.40% 1 0 1 Left Party V 4,286 700 596 1,293 2,363 666 1,369 470 419 12,162 6.63% 1 0 1 Christian Democrats KD 3,027 566 370 1,144 2,360 357 1,344 558 363 10,089 5.50% 0 1 1 Liberals L 2,970 322 250 818 1,654 250 1,123 415 156 7,958 4.34% 0 0 0 Green Party MP 2,043 355 388 701 1,645 232 880 366 163 6,773 3.69% 0 0 0 Feminist Initiative FI 187 29 86 63 149 30 51 32 15 642 0.35% 0 0 0 Alternative for Sweden AfS 190 44 22 86 154 34 74 15 14 633 0.35% 0 0 0 Citizens' Coalition MED 163 14 11 34 51 15 43 21 2 354 0.19% 0 0 0 Unity ENH 53 7 20 12 20 1 28 9 5 155 0.08% 0 0 0 Direct Democrats DD 46 4 7 15 36 8 13 6 2 137 0.07% 0 0 0 Pirate Party PP 52 9 1 12 17 15 18 2 1 127 0.07% 0 0 0 Independent Rural Party LPo 16 16 0 21 25 1 29 1 7 116 0.06% 0 0 0 Nordic Resistance Movement NMR 21 6 4 6 31 3 10 3 3 87 0.05% 0 0 0 Animals' Party DjuP 27 0 4 2 14 0 4 1 2 54 0.03% 0 0 0 Classical Liberal Party KLP 16 1 0 2 16 1 3 2 0 41 0.02% 0 0 0 Christian Values Party KrVP 12 7 5 1 7 0 0 2 1 35 0.02% 0 0 0 Initiative INI 13 1 3 0 3 0 3 1 0 24 0.01% 0 0 0 Basic Income Party BASIP 1 1 0 0 4 0 0 0 0 6 0.00% 0 0 0 Communist Party of Sweden SKP 1 0 0 1 0 0 0 0 0 2 0.00% 0 0 0 European Workers Party EAP 0 0 0 0 0 0 1 0 0 1 0.00% 0 0 0 Parties not on the ballot ÖVR 3 2 2 2 1 1 2 0 0 13 0.01% 0 0 0Valid votes 62,678 10,118 7,217 21,583 36,687 7,545 22,844 8,864 5,913 183,449 100.00% 9 1 10Blank votes 583 84 75 223 307 78 222 53 55 1,680 0.91% Rejected votes – unregistered parties 23 3 7 2 11 1 5 6 5 63 0.03% Rejected votes – other 51 2 8 8 24 7 13 3 4 120 0.06% Total polled 63,335 10,207 7,307 21,816 37,029 7,631 23,084 8,926 5,977 185,312 86.85% Registered electors 74,782 11,871 8,263 25,171 41,758 8,803 26,105 9,862 6,755 213,370 Turnout 84.69% 85.98% 88.43% 86.67% 88.68% 86.69% 88.43% 90.51% 88.48% 86.85%

The following candidates were elected: Constituency seats (party mandates) - Erik Bengtzboe (M), 228 votes; Hans Ekström (S), 964 votes; 2,051 votes; (M), 342 votes; Caroline Helmersson Olsson (S), 632 votes; Martina Johansson (C), 463 votes; Lotta Johnsson Fornarve (V), 429 votes; Adam Marttinen (SD), 238 votes; Fredrik Olovsson (S), 1,160 votes; and Roger Richthoff (SD), 57 votes. Levelling seats (party mandates) - (KD), 81 votes.

Permanent substitutions: Erik Bengtzboe (M) resigned on 26 April 2019 and was replaced by (M) on the same day. Jari Puustinen (M) resigned on 2 May 2019 and was replaced by Ann-Sofie Lifvenhage (M) on the same day. (M) resigned on 31 January 2021 and was replaced by Magnus Stuart (M) on 1 February 2021.

2014 Results of the 2014 general election held on 14 September 2014: