Adrian won a second gold medal as a member of the winning U.S. team in the 4×100-meter medley relay on the final day of the competition. He swam the anchor freestyle leg, with Matt Grevers swimming the backstroke leadoff leg, Brendan Hansen the breaststroke second leg, and Michael Phelps the butterfly third leg. The Americans recorded a time of 3:29:35, with the Japanese team taking the silver medal and the Australians receiving the bronze. In the race, Adrian had a split of 46.85, the fastest in the field.