Phelps handed over to Ryan Lochte, Peter Vanderkaay and Klete Keller to win in seven minutes 07.33 seconds.
The Australian quartet of Grant Hackett, Michael Klim, Nicholas Sprenger and Ian Thorpe finished second in 7:07.46.
Emiliano Brembilla, Massimilliano Rosolino, Simone Cercato and Filippo Magnini won bronze for Italy in 7:11:83
More from rediff