The 2004–05 OK Liga was the 36th season of the top-tier league of rink hockey in Spain.
Barcelona Sorli Discau finished the league as champion.
Sixteen teams joined the league.
The eight first teams at the end of the regular season qualified for the playoffs while the three last teams were relegated to Primera División.
Quarterfinals were played with a best-of-three format, while semifinals and final were played with a best-of-five series.
Seeded teams played games 1, 2 and 5 of the series at home.
The 2005 Copa del Rey was the 62nd edition of the Spanish men's roller hockey cup. It was played in Reus between the eight first qualified teams after the first half of the season.
Barcelona Sorli Discau won the title.