| Season | 2005 |
|---|---|
| Dates | Regular season: 15 May – 9 November 2005 Championship: 20 November – 4 December 2005 |
| Champions | Ulsan Hyundai Horang-i (2nd title) |
| Champions League | Ulsan Hyundai Horang-i Jeonbuk Hyundai Motors |
| Matches played | 156 |
| Goals scored | 373 (2.39 per match) |
| Best Player | Lee Chun-soo |
| Top goalscorer | Leandro Machado (13 goals) |
← 2004 2006 → | |
The 2005 K League was the 23rd season of the K League, South Korea's professional football league, from 15 May to 4 December. The format of the regular season and championship playoffs was the same as the one used in the 2004 season.
Busan IPark won the first stage, and the second stage was won by Seongnam Ilhwa Chunma. Two winners were guaranteed their slot in the end-of-season playoffs. Incheon United and Ulsan Hyundai Horang-i also joined the playoffs according to the overall table after two stages. In the semi-finals Ulsan defeated Seongnam 2–1, and Incheon defeated Busan 2–0. The two victorious teams faced each other in the two-legged championship final. Ulsan won the first leg 5–1 at the Incheon stadium, and though Incheon won the second leg 2–1, Ulsan lifted their second league title 6–3 on aggregate.
The first place team qualified for the championship playoffs.
| Pos | Team | Pld | W | D | L | GF | GA | GD | Pts | Qualification |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Busan IPark | 12 | 7 | 4 | 1 | 17 | 10 | +7 | 25 | Qualification for the playoffs |
| 2 | Incheon United | 12 | 7 | 3 | 2 | 20 | 13 | +7 | 24 | |
| 3 | Ulsan Hyundai Horang-i | 12 | 7 | 1 | 4 | 16 | 13 | +3 | 22 | |
| 4 | Pohang Steelers | 12 | 6 | 3 | 3 | 14 | 11 | +3 | 21 | |
| 5 | FC Seoul | 12 | 5 | 4 | 3 | 22 | 19 | +3 | 19 | |
| 6 | Seongnam Ilhwa Chunma | 12 | 4 | 4 | 4 | 18 | 15 | +3 | 16 | |
| 7 | Bucheon SK | 12 | 4 | 4 | 4 | 10 | 10 | 0 | 16 | |
| 8 | Daejeon Citizen | 12 | 2 | 8 | 2 | 11 | 11 | 0 | 14 | |
| 9 | Suwon Samsung Bluewings | 12 | 3 | 5 | 4 | 18 | 19 | −1 | 14 | |
| 10 | Jeonnam Dragons | 12 | 3 | 5 | 4 | 13 | 14 | −1 | 14 | |
| 11 | Jeonbuk Hyundai Motors | 12 | 2 | 3 | 7 | 13 | 19 | −6 | 9 | |
| 12 | Daegu FC | 12 | 2 | 3 | 7 | 14 | 25 | −11 | 9 | |
| 13 | Gwangju Sangmu Bulsajo | 12 | 1 | 3 | 8 | 16 | 23 | −7 | 6 |
The first place team qualified for the championship playoffs.
| Pos | Team | Pld | W | D | L | GF | GA | GD | Pts | Qualification |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Seongnam Ilhwa Chunma | 12 | 8 | 3 | 1 | 22 | 9 | +13 | 27 | Qualification for the playoffs |
| 2 | Bucheon SK | 12 | 8 | 2 | 2 | 16 | 8 | +8 | 26 | |
| 3 | Daegu FC | 12 | 6 | 3 | 3 | 15 | 11 | +4 | 21 | |
| 4 | Ulsan Hyundai Horang-i | 12 | 6 | 3 | 3 | 15 | 11 | +4 | 21 | |
| 5 | Incheon United | 12 | 6 | 3 | 3 | 16 | 13 | +3 | 21 | |
| 6 | Pohang Steelers | 12 | 5 | 4 | 3 | 14 | 11 | +3 | 19 | |
| 7 | Daejeon Citizen | 12 | 4 | 4 | 4 | 8 | 9 | −1 | 16 | |
| 8 | Suwon Samsung Bluewings | 12 | 3 | 5 | 4 | 11 | 13 | −2 | 14 | |
| 9 | FC Seoul | 12 | 3 | 4 | 5 | 15 | 13 | +2 | 13 | |
| 10 | Jeonnam Dragons | 12 | 4 | 1 | 7 | 10 | 15 | −5 | 13 | |
| 11 | Gwangju Sangmu Bulsajo | 12 | 3 | 2 | 7 | 7 | 15 | −8 | 11 | |
| 12 | Jeonbuk Hyundai Motors | 12 | 2 | 3 | 7 | 11 | 22 | −11 | 9 | |
| 13 | Busan IPark | 12 | 0 | 3 | 9 | 11 | 21 | −10 | 3 |
The top two teams in the overall table qualified for the championship playoffs.
| Pos | Team | Pld | W | D | L | GF | GA | GD | Pts | Qualification |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Incheon United | 24 | 13 | 6 | 5 | 36 | 26 | +10 | 45 | Qualification for the playoffs |
| 2 | Seongnam Ilhwa Chunma | 24 | 12 | 7 | 5 | 40 | 24 | +16 | 43 | Second stage winners |
| 3 | Ulsan Hyundai Horang-i | 24 | 13 | 4 | 7 | 31 | 24 | +7 | 43 | Qualification for the playoffs |
| 4 | Bucheon SK | 24 | 12 | 6 | 6 | 26 | 18 | +8 | 42 | |
| 5 | Pohang Steelers | 24 | 11 | 7 | 6 | 28 | 22 | +6 | 40 | |
| 6 | FC Seoul | 24 | 8 | 8 | 8 | 37 | 32 | +5 | 32 | |
| 7 | Daejeon Citizen | 24 | 6 | 12 | 6 | 19 | 20 | −1 | 30 | |
| 8 | Daegu FC | 24 | 8 | 6 | 10 | 29 | 36 | −7 | 30 | |
| 9 | Suwon Samsung Bluewings | 24 | 6 | 10 | 8 | 29 | 32 | −3 | 28 | |
| 10 | Busan IPark | 24 | 7 | 7 | 10 | 28 | 31 | −3 | 28 | First stage winners |
| 11 | Jeonnam Dragons | 24 | 7 | 6 | 11 | 23 | 29 | −6 | 27 | |
| 12 | Jeonbuk Hyundai Motors | 24 | 4 | 6 | 14 | 24 | 41 | −17 | 18 | Qualification for the Champions League [a] |
| 13 | Gwangju Sangmu Bulsajo | 24 | 4 | 5 | 15 | 23 | 38 | −15 | 17 |
| Semi-finals | Final | ||||||||||
| Busan IPark | 0 | ||||||||||
| Incheon United | 2 | ||||||||||
| Incheon United | 1 | 2 | 3 | ||||||||
| Ulsan Hyundai Horang-i | 5 | 1 | 6 | ||||||||
| Seongnam Ilhwa Chunma | 1 | ||||||||||
| Ulsan Hyundai Horang-i | 2 | ||||||||||
| Pos | Team | Qualification |
|---|---|---|
| 1 | Ulsan Hyundai Horang-i (C) | Qualification for the Champions League |
| 2 | Incheon United | |
| 3 | Seongnam Ilhwa Chunma | |
| 4 | Busan IPark |
This list includes goals of the championship playoffs.
| Rank | Player | Club | Goals | Apps |
|---|---|---|---|---|
| 1 |  Leandro Machado | Ulsan Hyundai Horang-i | 13 | 17 |
| 2 |  Park Chu-young | FC Seoul | 12 | 19 |
| 3 | Dudu | Seongnam Ilhwa Chunma | 10 | 24 |
| Sandro Hiroshi | Daegu FC | 10 | 24 | |
| 5 | Kim Do-hoon | Seongnam Ilhwa Chunma | 9 | 20 |
 Dženan Radončić | Incheon United | 9 | 22 | |
| Luciano Valente | Busan IPark | 9 | 22 | |
| Da Silva | Pohang Steelers | 9 | 24 | |
| 9 | Mota | Seongnam Ilhwa Chunma | 7 | 9 |
| Lee Chun-soo | Ulsan Hyundai Horang-i | 7 | 14 | |
 Adrian Neaga | Jeonnam Dragons | 7 | 15 | |
| Leandrão | Daejeon Citizen | 7 | 19 | |
| Nam Ki-il | Seongnam Ilhwa Chunma | 7 | 20 | |
| Kim Eun-jung | FC Seoul | 7 | 20 | |
| Selmir | Incheon United | 7 | 25 |
Source: [1]
