It will be the first time that Research in Motion, the Canadian company that produces the BlackBerry, has used an ad agency. Until now, it has relied on PR activity, word of mouth or promotion via mobile phone networks.
Leagas Delaney will initially work on a project basis, but will be handed a longer-term contract if the company is impressed with the results of the work produced.
Many business executives are compulsive users of their BlackBerrys - there are now 3.1 million users in the UK. The company is now looking to increase use among business and private consumers. Advertising is expected to attempt to persuade businesses that BlackBerrys are not only for senior managers.
Separately, Leagas Delaney has appointed Elliot Moss, formerly the client services director at Leo Burnett, as its managing director. Tim Delaney, the chief executive of Leagas Delaney, said: "Elliot has a rare combination - international experience on one of the world's most impressive brands with great enthusiasm for the business."