| Competition: | 1. divisjon |
| Season: | 2004 |
| Dates: | 12 April – 31 October |
| Winners: | Start |
| Promoted: | Start Aalesund |
| Relegated: | Raufoss Haugesund Vard Haugesund Tromsdalen |
| Matches: | 240 |
| Total Goals: | 832 |
| League Topscorer: | Paul Oyuga (18 goals) |
| Prevseason: | 2003 |
| Nextseason: | 2005 |
The 2004 1. divisjon was a Norwegian second-tier football season. The season kicked off on 12 April 2004, and the final round was played on 31 October 2004.
Start were promoted to the 2005 Tippeligaen as First Division winners, along with Aalesund who finished second. Start will be playing in the top division for the first time since 2002. Aalesund, meanwhile, returned to the top flight after being relegated in 2003.
As in previous seasons, there was a two-legged promotion play-off at the end of the season, between the third-placed team in the 1. divisjon (Kongsvinger) and the twelfth-placed team in the Tippeligaen (Bodø/Glimt). Bodø/Glimt kept their spot in the Tippeligaen, beating Kongsvinger 4–1 on aggregate.
| Rank | Scorer | Club | Goals |
|---|---|---|---|
| 1 |  Paul Oyuga | Bryne | 18 |
| 2 |  Magnus Myklebust | Hødd | 16 |
| 3 | Ben Wright | Start | 15 |
| Dag Roar Ørsal | Hødd | ||
| Morten Moldskred | Aalesund | ||
| Håvard Sakariassen | Moss | ||
| 7 | John Erling Kleppe | Pors Grenland | 14 |
| Bala Garba | Start | ||
| 9 | Mohammed Abdellaoue | Skeid | 11 |
| Henrik Nyhus | Mandalskameratene | ||
| Bjørn Yngvar Kydland | Bryne | ||
| Kim Larsen | Strømsgodset |
These two teams were relegated from the Tippeligaen in 2003. 12th-place finishers Vålerenga defeated Sandefjord in the playoff to retain their spot in the highest division.
These four teams were promoted from the 2. divisjon in 2003: