Geico filed its legal action this month at U.S. District Court in Alexandria, Va.

"Geico seeks an injunction against any further unauthorized use of its service marks by defendants in their advertising programs and to recover damages for defendants' illegal acts," the insurer's spokesperson said.

"This practice deliberately misleads consumers and allows Geico's competitors and these defendants to illegally exploit for their own commercial purposes Geico's investment of hundreds of millions of dollars in its brand," according to the spokesperson.

Yahoo said it can't discuss issues regarding pending lawsuits. Google's representatives did not immediately respond to a request for comment.

Geico said in its complaint that Google and Yahoo have been engaged in selling Geico's registered trademark name as search terms or "key words" to advertisers on defendants' Web sites and directing Web traffic to these advertisers' "sponsored listings" or "sponsor matches."

"As a means to generating advertising revenues for themselves," the Geico complaint stated, "defendants purport to sell the right to use Geico's nationally recognized service marks to third-party advertisers who have no connection to Geico and who seek to drive Internet traffic to their own Web sites when consumers perform a search using one of the famous Geico marks."

The complaint goes on to say that this practice has been taking place without Geico's consent or authorization and that it is causing confusion among consumers who are using Google and Yahoo search engines to contact or learn more about Geico.

In the case of Google, when a Web user typed in "Geico" as a search term, the search results also included a paid advertisement link listed as "Geico Auto Insurance: Save $300 California Auto Insurance" that led to the Web site of 21st Century Insurance Company, based in Woodland Hills, Calif.

The auto insurer's complaint states that this type of use of the famous Geico trademarked names "dilute their value and undermines Geico's investment of hundreds of millions of dollars in recent years to promote its auto insurance services under those marks through local and national radio, television, direct mail and print advertising."

The Chevy Chase, Md.-based Geico, a unit of Omaha, Neb.-based Berkshire Hathaway Inc., is currently the largest direct marketer of automobile insurance in the United States, as well as the fifth largest private-passenger auto insurer.