| Party | Leader | Description | Seats |
| Uri Party | | A left-wing, liberal/social-democratic party. It is the party of President Roh Moo-hyun and has a large majority in the National Assembly. The party gains its support from urban students, the young, and the Jeolla region. | 152 |
| Grand National Party | Park Guen Hye | A right-wing, conservative party. It is the largest opposition party in the National Assembly and leads the opposition camp. It is the heir of South Korea's traditionally conservative political elite. It gains its support from the conservative voters, rural areas, and the Gyeongsang region. | 121 |
| Democratic Labour Party | Gwon Yeong-Gil | A left-wing, socialist party. It is the third largest party in the National Assembly. It gains its support from farmers and industrial factory workers. | 10 |
| Millennium Democratic Party | | A left-wing, liberal/social-democratic. It used to be more successful, but a lot of its members left to join the Uri Party, with which discussions to merge are underway. It gains support from urban areas. | 9 |
| United Liberal Democrats | | A right-wing, conservative party. The party gains its support from rural areas. | 4 |
The following political parties are not currently represented in the National Assembly: