These are the Irish Recorded Music Association's number one albums of 2004, per the Top 100 Individual Artist Albums chart.
| Issue Date | Album | Artist |
|---|---|---|
| 1 January | Life for Rent | Dido |
| 8 January | ||
| 15 January | ||
| 22 January | ||
| 29 January | Talkie Walkie | Air |
| 5 February | ||
| 12 February | Feels like Home | Norah Jones |
| 19 February | ||
| 26 February | ||
| 4 March | Come Away with Me | |
| 11 March | Living | Paddy Casey |
| 18 March | Greatest Hits | Guns N' Roses |
| 25 March | ||
| 1 April | ||
| 8 April | ||
| 15 April | ||
| 22 April | ||
| 29 April | D12 World | D12 |
| 6 May | Greatest Hits | Guns N' Roses |
| 13 May | A Grand Don't Come for Free | The Streets |
| 20 May | Raining Down Arrows | Mundy |
| 27 May | Under My Skin | Avril Lavigne |
| 3 June | Borrowed Heaven | The Corrs |
| 10 June | Live 2004 | Planxty |
| 17 June | ||
| 24 June | ||
| 1 July | A Grand Don't Come for Free | The Streets |
| 8 July | Confessions | Usher |
| 15 July | A Grand Don't Come for Free | The Streets |
| 22 July | ||
| 29 July | ||
| 5 August | Scissor Sisters | Scissor Sisters |
| 12 August | Final Straw | Snow Patrol |
| 19 August | B-Sides | Damien Rice |
| 26 August | Songs about Jane | Maroon 5 |
| 2 September | ||
| 9 September | ||
| 16 September | Let's Bottle Bohemia | The Thrills |
| 23 September | Burn the Maps | The Frames |
| 30 September | ||
| 7 October | Around the Sun | R.E.M. |
| 14 October | Dreamed a Dream | George Murphy |
| 21 October | Greatest Hits | Robbie Williams |
| 28 October | ||
| 4 November | ||
| 11 November | Greatest Hits: My Prerogative | Britney Spears |
| 18 November | Encore | Eminem |
| 25 November | How to Dismantle an Atomic Bomb | U2 |
| 2 December | ||
| 9 December | ||
| 16 December | ||
| 23 December | ||
| 30 December |