The deal will see Bwin placed at the centre of promotional activities by Manchester United, the integration of Bwin into the club’s website and the creation of co-branded social gaming products.
Bwin will also gain access to Manchester United players for marketing campaigns and the inclusion of Bwin-branded match-day hoardings and betting kiosks at the club’s Old Trafford stadium.
The partnership is being further promoted with a prize draw to win Manchester United season tickets, which can be entered by placing £5 on a Manchester United related bet from a new or existing Bwin.com account.
The competition will be pushed via the Bwin website and updates on Twitter using the #backmanutd hashtag.
Norbert Teufelberger, co-chief executive of Bwin parent company bwin.party, said: "Football is fundamental to our long-term success, making up approximately half of our total sports betting revenue of €261m in 2011.
"As well as supporting our real-money gaming business, the agreement complements our recent move into social gaming.
"Man United has 569 million followers outside of Europe, providing us with a great opportunity to offer jointly designed and innovative products in countries that do not yet allow real money online sports betting."
The deal will complement Bwin’s existing sponsorship of Real Madrid and was announced by Sir Alex Ferguson, Rio Ferdinand, Nemanja Vidic and Wayne Rooney.