The agency will conduct a comprehensive overhaul of Brand Republic's online identity, site architecture and interface design.
Rufus Olins, the managing director of Haymarket Brand Media, said: "The redesigned site will provide a stronger platform for the magazines to publish breaking news and build a community among the marketing professionals that visit us every day to stay on top of their profession."
John Baker, the managing partner of OgilvyInteractive, who led the agency's pitch, added: "In the industry, the technology has changed to include video, user commenting and industry blogging. We are excited to help Haymarket take advantage of these changes.
"Brand Republic is one of only a few business websites that have become integral to the lives of their users. You can't be fully informed about what's happening in the industry without it."
The site, which includes the home pages of Campaign, Marketing and MediaWeek, was originally launched in September 2001.
As well as breaking more than 40 news stories every day it lists more than 3,200 jobs on its recruitment section and has an archive of more than 300,000 articles from across Haymarket's titles. It also publishes eight news bulletins a day.