Delcan Kidney makes a number of changes to the side that defeated Australia last weekend for Ireland's game against Russia on Sunday.
Keith Earls moves to the centre with
O'Gara starting at 10 and
Donnacha Ryan taking over from Stephen Ferris at blindside.
Leo Cullen captains the side in his first World Cup appearance. There are also first RWC appearances for
Fergus McFadden and
Paddy Wallace.
Ireland play Russia at Rotorua International Stadium on Sunday at 6am Irish time.
Ireland Team:
15 - Robert Kearney (UCD/Leinster)
14 - Fergus McFadden (Old Belvedere/Leinster)*
13 - Keith Earls (Young Munster/Munster)
12 - Paddy Wallace (Ballymena/Ulster)*
11 - Andrew Trimble (Ballymena/Ulster)
10 - Ronan O'Gara (Cork Constitution/Munster)
9 - Isaac Boss (Terenure College/Leinster)
1 - Cian Healy (Clontarf/Leinster)
2 - Sean Cronin (Leinster)
3 - Tony Buckley (Sale)
4 - Donncha O'Callaghan (Cork Constitution/Munster)
5 - Leo Cullen (Blackrock College/Leinster)* Captain
6 - Donnacha Ryan (Shannon/Munster)
7 - Sean O’Brien (Clontarf/Leinster)
8 - Jamie Heaslip (Naas/Leinster)
Replacements:
16 - Rory Best (Banbridge/Ulster)
17 - Mike Ross (Clontarf/Leinster)
18 - Denis Leamy (Cork Constitution/Munster)
19 - Shane Jennings (St.Mary's College/Leinster)
20 - Eoin Reddan (Lansdowne/Leinster)
21 - Jonathan Sexton (St. Mary's College/Leinster)
22 - Geordan Murphy (Leicester)
*Denotes RWC Debut