Ads for the pizzas will appear on Yahoo!'s home page and on its affiliated sites Yahoo! Mail, Yahoo! Calendar, Yahoo! Sports and My Yahoo!
Cost of the ad campaign was not disclosed.
A link to a special Pizza Hut site will allow users to receive more information about the chain's products, download coupons and enter a contest to win free pizza for a year.
Users can access the site after clicking on a Flash-based rich media ad on Yahoo!'s home page, which shows a wooden pizza paddle popping out of the page and pepperonis toppling down onto a pizza.