The 2004–05 Zurich Premiership was the 18th season of the top flight of the English domestic rugby union competitions.

[1] At the end of the season, Harlequins were relegated, to be replaced by Bristol for 2005–06.

As for the 2003–04 season, the first placed team automatically qualified for the final, where they played the winner of the second vs third place semi-final.

Note: Flags to the left of player names indicate national team as has been defined under World Rugby eligibility rules, or primary nationality for players who have not earned international senior caps.

Players may hold one or more non-WR nationalities.