The government-backed organisation, which aims to persuade businesses to reduce their carbon emissions, is gearing up for a high-profile campaign to be created by the two winning agencies, due to run this summer.
McCann will work on above-the-line and acquisition work, while Tequila is the lead direct and online agency. Both agencies are contracted until 2007. Tequila will subcontract media planning for the campaigns to Manning Gottlieb OMD.
Media buying, which was not included in the pitch, remains with Universal McCann, which has a contract with the trust until 2007.
Peter Hambly, the Carbon Trust's director of marketing and communications, said: "We are really pleased to have such a strong line of agency support in 2006-2007 and look forward to the campaign in June raising carbon emission reduction up the business agenda."
According to Nielsen Media Research, the Carbon Trust spent £4 million on advertising last year, predominantly on a campaign that highlighted climate change.