The 2004–05 European football season was the 101st season of Sport Lisboa e Benfica's existence and the club's 71st consecutive season in the top flight of Portuguese football. The season ran from 1 July 2004 to 30 June 2005; Benfica competed domestically in the Primeira Liga and the Taça de Portugal. The club also participated in the UEFA Champions League as a result of finishing second in the Primeira Liga in the previous season.