He was named in Ireland's squad for the 2007 Rugby World Cup on 12 August 2007. His campaign started against Namibia, who, despite being the lowest ranked team in the competition, only lost 32-17 to Ireland. After the game, O'Connell admitted: "A few of the more experienced guys need to start performing better and start leading the team a bit more." O'Connell lined out for another disappointing Irish performance six days later when Georgia came embarrassingly close to beating Ireland, eventually only losing 14-10. O'Connell's world cup ended after Ireland recorded two defeats against France and Argentina, meaning Ireland crashed out in the pool stage of the tournament in one of the lowest points in Irish rugby history.