The 2004–05 FA Cup was the 124th season of the world's oldest football competition, the FA Cup. The competition began on 28 August 2004, with the lowest-ranked of the entrants competing in the Extra preliminary round. For England's top 44 clubs, from the 2004–05 Premier League and 2004–05 Football League Championship, the FA Cup began at the third round in January.

The Football Association Challenge Cup, more commonly known as the FA Cup, is an annual knockout football competition in men's domestic English football. First played during the 1871–72 season, it is the oldest national football competition in the world. It is organised by and named after The Football Association. Since 2015, it has been known as Emirates FA Cup after its headline sponsor Emirates. A concurrent Women's FA Cup has been held since 1970.