Ford's biggest division announced the zero-percent financing late Thursday, and the offer through Oct. 31, as does GM's.
A Ford spokeswoman said ads for the new deals from WPP Group's J. Walter Thompson USA, Detroit, could break as early as this weekend.
GM announced its plan Sept. 19. Read the related story.
Both automakers have seen sales slide during the first eight months of August vs. a year ago. The companies said the new financing deals were aimed at keeping the U.S. economy moving.