10,625 athletes competed, some 600 more than expected, accompanied by 5,501 team officials from 201 countries.
There were 301 medal events in 28 different sports.
Athens 2004 marked the first time since the 1996 Summer Olympics that all countries with a National Olympic Committee were in attendance. 2004 marked the return of the games to the city where they began.
A new medal obverse was introduced at these Games, replacing the design by Giuseppe Cassioli that had been used since the 1928 Games. This rectified the long lasting mistake of using a depiction of the Roman Colosseum rather than a Greek venue. The new design features the Panathinaiko Stadium. The 2004 summer games were hailed as "unforgettable, dream games" by IOC President Jacques Rogge, and left Athens with a significantly improved infrastructure, including a new airport, ring road, and subway system.
Athens was chosen as the host city during the 106th IOC Session held in Lausanne on 5 September 1997.