These are the Irish Recorded Music Association's number one albums of 2009, per the Top 100 Individual Artist Albums chart.
| Issue Date | Album | Artist |
|---|---|---|
| 1 January | The Circus | Take That |
| 8 January | I Am... Sasha Fierce | Beyoncé |
| 15 January | ||
| 22 January | Songs for You, Truths for Me | James Morrison |
| 29 January | Working On A Dream | Bruce Springsteen |
| 12 February | The Fame | Lady Gaga |
| 26 February | Blue Lights on the Runway | Bell X1 |
| 5 March | No Line On the Horizon | U2 |
| 13 March | ||
| 20 March | The Fame | Lady Gaga |
| 27 March | Songs for My Mother | Ronan Keating |
| 2 April | The Fame | Lady Gaga |
| 9 April | Eoghan Quigg | Eoghan Quigg |
| 16 April | The Fame | Lady Gaga |
| 23 April | Listen | Christy Moore |
| 21 May | Relapse | Eminem |
| 11 June | Sunny Side Up | Paolo Nutini |
| 18 June | Love Tattoo | Imelda May |
| 25 June | ||
| 2 July | The Essential Michael Jackson | Michael Jackson |
| 9 July | ||
| 16 July | ||
| 23 July | ||
| 30 July | ||
| 6 August | ||
| 13 August | The Script | The Script |
| 20 August | ||
| 27 August | Humbug | Arctic Monkeys |
| 3 September | The Script | The Script |
| 10 September | ||
| 17 September | The Resistance | Muse |
| 24 September | Celebration | Madonna |
| 1 October | Brand New Eyes | Paramore |
| 8 October | Celebration | Madonna |
| 15 October | She Wolf | Shakira |
| 22 October | Crazy Love | Michael Bublé |
| 29 October | ||
| 5 November | ||
| 12 November | JLS | JLS |
| 19 November | ||
| 26 November | I Dreamed a Dream | Susan Boyle |
| 3 December | ||
| 10 December | ||
| 17 December | Crazy Love | Michael Bublé |
| 24 December | ||
| 31 December |