The media account has moved to Universal McCann Manchester from MCS.
Budgets are undisclosed, although the company is committed to spending £500 million in opening a further 172 stores over the next five years. Sue Little, the McCann chief executive, will run the account along with a 25-strong team.
Aldi, which has 278 outlets across Britain, spends £5.6 million on advertising, according to Nielsen Media Research.
The decision to move its creative advertising business from London's Carney Richardson without a pitch is part of an effort to improve on a disappointing UK performance over the past 15 years that has seen it capture less than 1 per cent of the market.