MetLife is asking the U.S. District Court for the Southern District of New York to stop AT&T Wireless' "mlife" campaign from WPP Group's Ogilvy & Mather, New York.
MetLife claims AT&T Wireless' effort is too similar to its "Have your MetLife today?" ads.
In a statement, AT&T Wireless said the claim is without merit.
"Last time we checked, everyone is still free to use the thirteenth letter of the alphabet," the statement said. The theme "mlife" stands for "mobile life."