The men’s 4 × 100 metre medley relay event at the 2012 Summer Olympics took place on 3–4 August at the London Aquatics Centre in London United Kingdom.In the final race of his unprecedented career before an official retirement Michael Phelps topped off with his eighteenth gold and twenty-second overall to officially become the most decorated Olympian of all time as the U.S. men’s team posted a textile best to defend the Olympic medley relay title since the event’s inception in 1960.