| 2004 State of Origin series | |
|---|---|
| Won by |  New South Wales (11th title) |
| Series margin | 2–1 |
| Points scored | 107 |
| Attendance | 203,309 (ave. 67,770 per match) |
| Player of the series | Craig Fitzgibbon |
| Top points scorer(s) | Craig Fitzgibbon (20) |
| Top try scorer(s) |  Billy Slater (3) |
The 2004 State of Origin series was the 23rd time that the annual three-game series between the Queensland and New South Wales representative rugby league football teams was contested entirely under 'state of origin' selection rules.
A pre-series Blues mobile phone scandal, Brad Fittler's comeback, a Golden point outcome in Game I and an extraordinary Billy Slater try showed that State of Origin's ability to create memorable football moments was as strong as ever after 25 years of the concept. The New South Wales' Game III victory saw a match-up in the respective cumulative tallies at 35 wins apiece, continuing a recurring trend where any push toward dominance by one side is soon countered by the other. The Ron McAuliffe Medal for Queensland player of the series was awarded to Steve Price.