The agency will work across a range of media, including online and direct mail, to recruit new customers and cross-sell to existing customers.
Betfair is the trading name of The Sporting Exchange and was founded in 2000 by former traders Andrew Black and Edward Wray. Today, the company employs nearly 1,000 staff and has 800,000 registered customers worldwide.
While a traditional betting shop sets its own odds, Betfair allows customers to bet against odds set by other gamblers, so one person can place odds on the site and see if other customers are attracted to the wager.
Peter Janes, Betfair's retention and CRM director, said: "We will be working with Flourish to develop communications that reinforce Betfair's points of difference: better choice, value and control."
Since being founded two-and-a-half years ago, the Bristol-based agency has been named fastest-growing direct agency outside of London in Marketing's 2006 Direct Marketing League.
Its client roster includes Camelot, BSkyB and Chelsea Building Society. It has recently expanded its portfolio picking up the account for German-owned insurance firm Allianz Cornhill to handle customer retention as well as acquisition.
Richard Hartson, director and co-founder of Flourish, said: "Befair's energy passion for the market is infectious and we look forward to working alongside them."
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