Phelps and his team -- Ryan Lochte, Ricky Berens, and Conor Dwyer -- picked up gold for the United States, with Phelps beating out France in the final stretch by almost a body length. China took bronze.
Phelps won his 18th earlier today -- a silver -- during the 200m butterfly.
In addition to the all-time Olympic medal record, Phelps also holds the all-time record for most gold Olympic medals (15), and the record for most gold medals in individual events (9).
The previous all-time Olympic medal count was held by Soviet gymnast Larisa Latynina, who won 18 total medals over 3 Olympics.
USA! USA! USA! USA! USA! USA! USA!