The 2007–08 Adelaide United FC season was the club's third season since the inception of the A-League. The club competed in the 2007–08 A-League and finished sixth on the ladder. For the 2007–08 season Adelaide recruited ex-Socceroo Paul Agostino "marquee", Ivorian Jonas Salley and ex-Olyroo Kristian Sarkies. They also signed Issy Erdogan of Preston Lions. One of the success stories of the season was the signing of former Flamengo FC player Cássio on a free transfer from Brazilian club. Cássio, who joined from Santa Cruz FC, won the Club Champion award in his first season. Shaun Ontong and Matthew Mullen from the AIS, were also signed to replenish their defensive stocks after the departure of Kristian Rees, Adam van Dommele and Aaron Goulding.