The best selling album in 2004 in Ireland was HOW TO DISMANTLE AN ATOMIC BOMB by U2.
| Rank | Artist | Album | Released |
| 1 | U2 | HOW TO DISMANTLE AN ATOMIC BOMB | 2004 |
| 2 | PADDY CASEY | LIVING | 2003 |
| 3 | GUNS N' ROSES | GREATEST HITS | 2004 |
| 4 | MAROON 5 | SONGS ABOUT JANE | 2002 |
| 5 | SNOW PATROL | FINAL STRAW | 2003 |
| 6 | DAMIEN RICE | O | 2002 |
| 7 | ROBBIE WILLIAMS | GREATEST HITS | 2004 |
| 8 | BRITNEY SPEARS | GREATEST HITS: MY PREROGATIVE | 2004 |
| 9 | USHER | CONFESSIONS | 2004 |
| 10 | THE STREETS | A GRAND DON'T COME FOR FREE | 2004 |
| 11 | EMINEM | ENCORE | 2004 |
| 12 | SCISSOR SISTERS | SCISSOR SISTERS | 2004 |
| 13 | NOW SERIES (UK) | NOW THAT'S WHAT I CALL MUSIC! 57 | 2004 |
| 14 | LUKE KELLY | BEST OF | 2004 |
| 15 | KEANE | HOPES AND FEARS | 2004 |
| 16 | NOW SERIES (UK) | NOW THAT'S WHAT I CALL MUSIC! 59 | 2004 |
| 17 | NOW SERIES (UK) | NOW THAT'S WHAT I CALL MUSIC! 58 | 2004 |
| 18 | ANASTACIA | ANASTACIA | 2004 |
| 19 | MARIO ROSENSTOCK | GIFT GRUB - THE BEST OF 2004 | 2004 |
| 20 | NORAH JONES | FEELS LIKE HOME | 2004 |
Source: IRMA