Coach Declan Kidney has also retained Ulster's Paddy Jackson despite the fly-half coming in for criticism following his performance in Scotland, while Leinster's uncapped Ian Madigan is also included in the 32 man squad as cover.
Ireland have suffered a series of injury setbacks during this year's Championship, but Kidney has included Mike McCarthy, Donnacha Ryan and Craig Gilroy in his squad suggesting the previously sidelined trio are fit for selection.
But it is Kidney's decision to omit O'Gara - who turns 36 on Thursday - which will hog the headlines with this being the first time the 128-cap veteran has been left out of a matchday squad when fully fit for 13 years.
O'Gara has struggled when called upon in this year's Championship but showed a return to form for Munster on Saturday as the Irish region drew 13-13 with Ospreys in the Pro12.
And Munster coach Rob Penney was quick to praise the qualities of O'Gara as his glittering international career appears to be coming to an end.
"He did really well. He has had a tough couple of weeks and it shows how resilient the man is," said Penney. "He has still got a lot left to offer."