In Coughlin's second Olympics appearance, at Beijing in 2008, she became the first American female athlete to win six medals in one Olympics. She was elected joint captain of the US women's swimming team together with five-time Olympian Dara Torres and four-time Olympian Amanda Beard. Coughlin won the gold medal in the 100-meter backstroke at those Olympiads, the inaugural woman to successfully defend a gold medal standing in that event. her world records was surpassed in the semi final by Kirsty Coventry, would take the silver. Standing on the medal platform, her lip was still bleeding having bitten it during the race to distract her from the pain in her legs. She won a silver medal in the 4×100-meter freestyle relay, swimming with Lacey Nymeyer, Kara Lynn Joyce and Dara Torres, and also won bronze medals in the 200-meter individual medley, 4×200-meter freestyle relay, and the 100-meter freestyle. She won a silver medal in her final race in the 4×100-meter medley relay swimming with Rebecca Soni, Christine Magnuson, and Dara Torres.