Draft, the incumbent on Saab, knocked out MRM Partners and TBWA\GGT, the incumbent on Vauxhall, to secure the business.
DLKW Dialogue, whose sister advertising agency Delaney Lund Knox Warren & Partners works on Vauxhall's advertising account, was also involved.
It has created some below-the-line projects for Vauxhall, mostly digital.
The decision is a blow for TBWA\GGT; Vauxhall was one of its biggest clients and it had held the business for 14 years. Draft had handled the Saab account for five years.
The pitch for the UK direct marketing business was called in January as part of an efficiency drive by GM. It has been combining the back office operations of Vauxhall and Saab and has included marketing in this process.
The review was in keeping with GM's decision to centralise its £98 million Daewoo, Saab and Vauxhall media accounts into IPG's Initiative last September, with Universal McCann losing Saab.
Interpublic's MRM Partners handles the pan-European direct marketing business for Vauxhall across Europe, where it is known as Opel.
David Crundwell, the manager of business affairs at Saab and Vauxhall, confirmed the appointment of Draft. "The decision was based on a combination of factors, one of which was an understanding of what we wanted that was most closely aligned with our plans," he said.
The car maker's above-the-line account is split between Lowe and DLKW in the UK. Vauxhall invites both agencies to pitch for its briefs as and when they arise. Lowe handles the Zafira and the Meriva and has a diesel campaign on air. DLKW created the Astra relaunch campaign.
Interpublic has a significant minority stake in DLKW.