The review covers the UK, Germany, France, Spain, Italy and Greece. The incumbent on the UK account is UM London, which won the business in February 2010.
Bwin's central client team in Austria is handling the process. It is understood that the brand has ambitions to spend close to £50 million on media to support its European advertising in the coming year as it looks to make gains on its gaming competitors.
In August, the company signed a three-year sponsorship deal with Manchester United to be the club's "official online gaming and betting partner". Bwin is also the shirt sponsor of Real Madrid and a partner with Bayern Munich.
In February, Wieden & Kennedy Amsterdam created an advertising campaign for the company featuring members of the Real Madrid team.
Bwin has struggled within its key market of Germany recently due to regulatory issues in the industry, which has affected the company's share price. Bwin is also looking to improve its position in Spain.
In March last year, Bwin Interactive Entertainment merged with its competitor PartyGaming to create the world's biggest listed online gaming business under the company name Bwin.Party Digital Entertainment.Follow @KatherinePLevy