The members of the seventeenth National Assembly of South Korea were elected on 15 April 2004. The Assembly sat from 30 May 2004 until 29 May 2008.[1]
| Date | Constituency | Incumbent | Party | New member | Party | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 6 January 2005 | Proportional representation | Park Hong-soo | bgcolor= | Uri | Suh Hae-suk | Uri | Incumbent resigned on 6 January 2005 upon appointment as Minister of Agriculture; replaced by the next member in the Uri list. | ||
| 23 March 2005 | Proportional representation | Park Se-il | Grand National | Lee Sung-ku | Grand National | Incumbent resigned on 23 March 2005; replaced by the next member in the Grand National list. | |||
| 30 April 2005 | Jungwon, Seongnam, Gyeonggi Province | Lee Sang-rak | Uri | Shin Sang-jin | Grand National | Incumbent lost seat on 10 December 2004. New member by-elected. | |||
| Pocheon–Yeoncheon, Gyeonggi Province | Lee Chul-woo | Uri | Ko Jeou-heung | Grand National | Incumbent lost seat on 28 March 2005. New member by-elected. | ||||
| Gongju–Yeongi, South Chungcheong Province | Oh Si-duck | Uri | Chung Jin-suk | Independent | Incumbent lost seat on 28 January 2005. New member by-elected. | ||||
| Asan, South Chungcheong Province | Bok Ki-wang | Uri | Lee Jin-koo | Grand National | Incumbent lost seat on 10 March 2005. New member by-elected. | ||||
| Yeongcheon, North Gyeongsang Province | Lee Duk-mo | Grand National | Chung Hee-soo | Grand National | Incumbent lost seat on 18 February 2005. New member by-elected. | ||||
| Gimhae A, South Gyeongsang Province | Kim Maeng-gon | Uri | Kim Chung-kwon | Grand National | Incumbent lost seat on 27 March 2005. New member by-elected. | ||||
| 13 October 2005 | Proportional representation | Yoo Seong-min | Grand National | Moon Hee | Grand National | Incumbent resigned on 13 October 2005 to run in the 2005 Dong B, Daegu by-election; replaced by the next member in the Grand National list. | |||
| 26 October 2005 | Dong B, Daegu | Park Chang-dal | Grand National | Yoo Seong-min | Grand National | Incumbent's election invalidated on 15 September 2005. New member by-elected. | |||
| Buk, Ulsan | Cho seung-soo | Democratic Labor | Yoon Doo-hwan | Grand National | Incumbent lost seat on 29 September 2005. New member by-elected. | ||||
| Wonmi A, Bucheon, Gyeonggi Province | Kim Ki-suk | Uri | Lim Hae-kyu | Grand National | Incumbent lost seat on 24 May 2005. New member by-elected. | ||||
| Gwangju, Gyeonggi Province | Park Hyuk-kyu | Grand National | Chung Chin-sup | Grand National | Incumbent lost seat on 9 September 2005. New member by-elected. | ||||
| 26 July 2006 | Seongbuk B, Seoul | Shin Geh-ryoon | Uri | Chough Soon-hyung | Democratic | Incumbent lost seat on 10 February 2006. New member by-elected. | |||
| Songpa A, Seoul | Maeng Hyung-kyu | Grand National | Maeng Hyung-kyu | Grand National | Incumbent resigned on 31 January 2006 to run in the 2006 Seoul mayoral election; re-elected in the by-election. | ||||
| Sosa, Bucheon, Gyeonggi Province | Kim Moon-soo | Grand National | Cha Myong-jin | Grand National | Incumbent resigned on 31 January 2006 to run in the 2006 Gyeonggi Province gubernatorial election. New member by-elected. | ||||
| Masan A, South Gyeongsang Province | Kim Jung-boo | Grand National | Lee Ju-young | Grand National | Incumbent lost seat on 12 May 2006. New member by-elected. | ||||
| 28 September 2006 | Proportional representation | Kim Hong-il | Democratic | Kim Song-ja | Democratic | Incumbent lost seat on 28 September 2006; replaced by the next member in the Democratic list. | |||
| 25 October 2006 | Namdong B, Incheon | Lee Ho-woong | Uri | Lee Weon-bok | Grand National | Incumbent lost seat on 14 September 2006. New member by-elected. | |||
| Haenam–Jindo, South Jeolla Province | Lee Jung-il | Democratic | Chae Il-byung | Democratic | Incumbent lost seat on 25 August 2006. New member by-elected. | ||||
| 1 February 2007 | Proportional representation | Chung Duck-koo | Uri | Shin Myoung | Uri | Incumbent lost seat on 1 February 2007; replaced by the next member in the Uri list. | |||
| 25 April 2007 | Seo B, Daejeon | Ku Non-hoe | Uri | Sim Dae-pyung | Uri | Incumbent died on 5 November 2006. New member by-elected. | |||
| Hwaseong, Gyeonggi Province | Ahn Byong-yub | Uri | Ko Hee-sun | Grand National | Incumbent's election invalidated on 10 November 2006. New member by-elected. | ||||
| Muan–Sinan, South Jeolla Province | Hahn Hwa-kap | Democratic | Kim Hong-up | Democratic | Incumbent lost seat on 22 December 2006. New member by-elected. | ||||
| 15 October 2007 | Proportional representation | Kim Hyuk-kyu | GUDNP (elected as Uri) | Kim Young-dae | GUDNP (from Uri list) | Incumbent lost seat on 15 October 2007; replaced by the next member in the Uri list. | |||
| 13 December 2007 | Busanjin A, Busan | Kim Byung-ho | Independent (elected as Grand National) | Seat remained vacant | Incumbent lost seat on 13 December 2007. No by-election held. | ||||
| 14 February 2008 | Proportional representation | Sim Sang-jeung | Democratic Labor | Seat remained vacant | Incumbent lost seat on 14 February 2008. | ||||
| Proportional representation | Roh Hoe-chan | Democratic Labor | Seat remained vacant | Incumbent lost seat on 14 February 2008. | |||||
| 20 February 2008 | Proportional representation | Dan Byung-ho | Democratic Labor | Seat remained vacant | Incumbent lost seat on 20 February 2008. | ||||