Nicholas Hall, head of marketing at Gocompare.com, said: "MEC won the business after demonstrating their ability to develop a robust media strategy that will help us to achieve our sales targets for 2007 and beyond."
The insurance aggregator website, which specialises in comparing car insurance quotes, also kicked off a creative review last month, which is ongoing.
The winning agency will be briefed with an initial project to create two TV commercials for GoCompare.
GoCompare spent £2.3m on media in the 12 months ended June 30, according to figures supplied by Nielsen Media Research. Its budget was almost entirely spent on TV advertising.