The revamped homepage, which is accessed by nearly 16m users a month, will go live later this week. It will carry bigger advertising spaces that can be tailored to advertisers' needs.
A lot of the clutter which has previously been associated with the MSN homepage, including smaller advertising formats such as skyscrapers and banner ads, is being ditched as part of the company's rethink.
MSN is also improving navigation, with clear links to its other services, such as Hotmail and Messenger.
Chris Ward, MSN UK's commercial director, said that it had consulted with both advertisers and media agencies before deciding on the changes, which it hoped would attract traditional advertisers not yet using online.
'A lot of growth has been driven by direct-response advertisers, so we want to build on the branding potential by giving advertisers new opportunities,' he added.
The relaunch comes just a week after industry body the Interactive Advertising Bureau (IAB) revealed that online adspend grew by 80% in 2003, topping £350m.
Advertisers new to online, including McDonald's and Coca Cola, are behind the web ad boom.