The project will have particular emphasis on Europe - especially the UK, Italy, Spain and Ireland - and the US, where Ladbrokes has invested heavily in internet gambling.
M&C will be briefed to reassess the Ladbrokes brand, develop a brand strategy and produce all of the creative work. This will also include a number of TV executions in the UK following the deregulation of Sports Book Betting in September.
The Gambling Act 2006 effectively removed bans on betting and gaming ads being broadcast on television or radio as long as they are "socially responsible".
This means that any advertising must not target children or suggest that gambling can lead to sexual success or enhance attractiveness.
The Advertising Standards Authority will enforce the rules with Ofcom and the Gambling Commission.
Leo Burnett will not be affected by the appointment.