Publicis-owned ZenithOptimedia won the business after a final shoot-out against Omnicom's PHD.
Insurance specialist BGL kicked off a media review through the AAR in September, originally shortlisting ZenithOptimedia, PHD, MindShare, Carat and incumbent MediaVest Manchester, which has held the account for five years.
BGL Group's brands include comparethemarket.com, Budget Insurance, Dial Direct, motorbike insurance specialist Bennetts and carbon-neutral car insurer Ibuyeco.
The review decision followed the appointment in July of Kal Samra, previously in charge of Bennetts, as managing director of BGL Group.
In the wake of recent growth, BGL has earmarked £30m for its combined marketing budgets next year, the bulk of which is understood to be online media spend. At least £20m of this will be for comparethemarket.com, including £5m in sponsorship.
This is the second win for the Publicis agency in as many weeks. Last week, ZenithOptimedia won the communications planning and media buying account for Constellation Europe's wine brands - worth £15m, according to Zenith.
The agency beat off competition from incumbent AMS Media, which has held on to Constellation's cider brands, and WPP's MediaCom.
In September, Zenith won a hard-fought battle against Walker Media to retain its hold on the £26m media planning and buying account for furniture retailer MFI.
BGL Group, formerly known as Budget Group of Companies, was founded in 1992.
It now provides insurance for more than 1.75 million customers, with operations in Peterborough, Coventry, Sunderland and Peterlee in the UK and Cape Town in South Africa.
BGL cites its most established brands as Budget Insurance - for cars, vans and homes - and Dial Direct.
Comparethemarket.com signed a £5m sponsorship deal with Channel 4 earlier this year for the broadcaster's drama programming for 12 months from June 2007.
VCCP produced a series of more than 40 idents for the sponsorship, focusing on the site's car insurance service, to run across shows including Studio 60, Shameless and Brothers and Sisters.