We demonstrate that matching ad format to a consumer's mode of information processing enhances advertising effectiveness. Relative to noncomparative ads, comparative ads are more effective when consumers use analytical processing. Conversely, noncomparative ads are more effective than comparative ads when consumers use imagery processing. When ad format is compatible with processing mode, information processability is enhanced, making the message more persuasive and ad evaluations, brand evaluations, and purchase intentions more favorable than when ad format and processing mode are incompatible.