DDB London won the business after what was a "particularly competitive pitch" four-way pitch against Soul, WCRS and Miles Calcraft Briginshaw Duffy.
The appointment was made by to promote the three ballots taking place on June 10 -- the London Mayor, the London Assembly and European Parliament.
DDB London is charged with creating a campaign to highlight the elections, which will include telling people how and when to vote and point voters in the right direction for further information. Spend for the campaign is expected to be around £1.5m, with ZenithOptimedia handling media planning. It is likely to include press, radio and outdoor.
Andrew Nye, head of communications at London Elects, said: "We appointed DDB after a particularly competitive pitch. It demonstrated clear thinking and strong creative ideas that are in line with our remit to explain how London's elections on June 10 work."
The London Elects advertising will run in addition to UK-wide activity planned by the Electoral Commission, telling people when and why they should vote. This work will be developed by St Luke's.
Livingstone yesterday won the Mayoral candidacy three weeks after he regained his party's support and backing. He lost it after he decided to run against the official Labour candidate Frank Dobson after losing out in a controversial selection process.
Overall Livingstone was backed by 93.9% of members with less than 6% voting against him.
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