Leeds-based Zenith will provide 550 Asda drivers with cars through a solus-badge arrangement with Vauxhall. The deal will increase Zenith's fleet to more than 9,000 vehicles.
The fleet will be funded by contract hire and Zenith will provide management with an in-house team based at Asda House in Leeds.
As part of its outsourcing facility, Asda staff will use Zenith's online fleet and accident management service.
Andy Potter, from Asda's commercial development team, said: 'This deal will provide Asda with great service to its colleagues from a local growing company.'
Philip Jerome, sales and marketing director at Zenith, said: 'Asda is a major blue-chip company and this is an endorsement of not only our investment in product innovation and online technology but of the quality and commitment of the whole Zenith team.'