The multiyear agreement, starting in June, lets Google sell almost 5 percent of Clear Channel's advertising inventory during all programs and all times of the day, across more than 675 stations nationwide, the companies said.
The companies did not disclose terms of the agreement, but Clear Channel will get most of the ad revenue, the companies said.
Google's hundreds of thousands of online advertisers will easily be able to buy Clear Channel radio spots through Google's Web-based ad-sales system, the companies said.
Advertisers will be allowed to specify the markets and types of radio stations on which they want their ad to be played, but not which specific Clear Channel radio stations will play it.
Calling the deal "a true win-win," Clear Channel Chief Executive John Hogan said his company would get "access to an entirely new group of advertisers within a new and complementary sales channel" and Google would add another advertising option for its customers.
Google recently started selling ads for the 125 national satellite channels on EchoStar Communications Corp.'s DISH Network.