In July 2004, Edmílson signed with FC Barcelona for a reported €10 million. He made his La Liga debut on 19 September in a 1–1 away draw against Atlético Madrid, and finished his debut campaign with only six matches as the Catalans won the national championship; on 3 October, after having come on as a substitute for Samuel Eto'o during a home fixture against CD Numancia, he himself had to be substituted after only five minutes on the pitch, going on to be sidelined for several months.