He has won 14 career Olympic Gold medals, the most by any Olympian. As of 2008, Phelps holds seven world records in swimming. Phelps holds the record for the most gold medals at a single Olympics, his eight at the 2008 Beijing Olympics, surpassing American swimmer Mark Spitz's seven gold performance at Munich in 1972. Overall, Phelps has won 16 Olympic medals: six gold and two bronze at Athens in 2004, and eight gold at Beijing in 2008. In doing so he has twice equaled the record eight medals of any type at a single Olympics achieved by Soviet gymnast Alexander Dityatin at the 1980 Moscow Summer Games. His five golds in individual events tied the single Games record set by Eric Heiden in the 1980 Winter Olympics and equaled by Vitaly Scherbo at the 1992 Summer Games. Phelps' career Olympic medal total is second only to the 18 that Soviet gymnast Larissa Latynina won over three Olympics, including nine gold.

Phelps's international titles and record breaking performances have earned him the World Swimmer of the Year Award in 2003, 2004, 2006, 2007, and 2008 and American Swimmer of the Year Award in 2001, 2002, 2003, 2004, 2006, 2007, and 2008. He has won a total of 48 career medals thus far in major international competition, forty gold, six silver, and two bronze spanning the Olympics, the World, and the Pan Pacific Championships.

His unprecedented Olympic success in 2008 earned Phelps Sports Illustrated magazine's Sportsman of the Year award.