On 9 October 2011 during the 2011 Rugby World Cup, Muliaina played his 100th game for the All Blacks after starting at fullback against Argentina. During the game, Muliaina was forced from the field at half-time, having injured his shoulder. This was later revealed to have been fractured, meaning he was dropped from the New Zealand World Cup squad. Muliaina retired from the All Blacks squad the following day on 10 October 2011 after achieving his 100th Test cap and returned on 23 October 2011 to claim his gold medal after the All Blacks won the 2011 Rugby World Cup Final.