The agency’s Birmingham office won the business following a pitch with several undisclosed agencies.
It is believed the incumbents Delaney Lund Knox Warren and Luton-based agency BMB repitched for the account.
McCann Erickson will commence work in November and encompasses GM’s Vauxhall, Saab and Chevrolet brands.
The agency will be responsible for co-ordinating the marketing of 697 UK retailers and managing a team of regional marketing consultants.
The review process was overseen by GM head of retail marketing Richard Hughes.
It is the latest win for the agency network which this year was also awarded the £70m pan-European ad account to launch GM’s latest Astra model.
McCann Erickson Frankfurt is handling the brief for the Vauxhall marque which will be unveiled in September.
It is expected to be GM’s biggest marketing push since it announced plans to sell off its European business earlier this year.
The Frankfurt office won the account following a pitch against Lowe Germany and Delaney Lund Knox Warren.