MEC retained the £5 million account after a review launched in February last year that resulted in a pitch process also involving Carat, Starcom and Universal McCann.
Transport for London spent approximately £5 million on advertising last year, according to The Nielsen Company, but its 2011 ad budget is unclear in light of public-sector ad cuts.
The contract covers advertising to promote the London Underground, buses, congestion charging, road safety, river services, taxis and licensed cabs, Victoria Coach Station and road traffic enforcement.
The tender also stated that the brief may include requirements from the Olympic Delivery Authority in the run-up to the London 2012 Olympics.
Last May, Transport for London also launched a statutory pitch for its creative business, held by WCRS and M&C Saatchi. However, this was suspended two months later along with a digital advertising review after the Government announced that Transport for London's overall budget would shrink by £108 million, impacting on the organisation's ability to advertise.