On 2 June 2008, Özdemir announced his candidacy as co-chair of his party.
Özdemir's rival candidate was Volker Ratzmann, leader of the Green parliamentary group in the Berlin House of Representatives, who eventually withdrew his candidacy on 4 September 2008 for personal reasons.

In the run-up to the party co-chair elections, Özdemir also ran for a promising party list position for the 2009 German elections at the federal state party conference of Baden-Württemberg.
In two separate runs he lost to his respective direct opponents.
Nevertheless, Özdemir adhered to his candidacy for the party chairmanship.

Since 15 November 2008, Özdemir has been one of two co-chairs of Alliance '90/The Greens.
He received 79.2 percent of the delegate votes.

In the 2009 elections, Özdemir was not elected to the Bundestag.
As a candidate in the constituency of Stuttgart I, which covers south Stuttgart he polled 29.9%, but lost to Stefan Kaufmann, the candidate of the CDU.
On 2 June 2008, Özdemir announced his candidacy as co-chair of his party. Özdemir's rival candidate was Volker Ratzmann, leader of the Green parliamentary group in the Berlin House of Representatives, who eventually withdrew his candidacy on 4 September 2008 for personal reasons.
In the run-up to the party co-chair elections, Özdemir also ran for a promising party list position for the 2009 German elections at the federal state party conference of Baden-Württemberg. In two separate runs he lost to his respective direct opponents. Nevertheless, Özdemir adhered to his candidacy for the party chairmanship.
Since 15 November 2008, Özdemir has been one of two co-chairs of Alliance '90/The Greens. He received 79.2 percent of the delegate votes.
In the 2009 elections, Özdemir was not elected to the Bundestag. As a candidate in the constituency of Stuttgart I, which covers south Stuttgart he polled 29.9%, but lost to Stefan Kaufmann, the candidate of the CDU.
Cem Özdemir