The Korea National League 2004 was the second season of the second highest South Korean football league under this name. The game was played in 2 rounds. The winners of each round played for the title in the championship game. The first defending champion of the Korea National League was Goyang KB Kookmin Bank FC . The defending champion became second champion.
The best of the first and second half of the season took part in the championship games. The championship was played through a return leg. The winner became Korea National League champion. The games were played on November 20th and 27th.