This essay traces the logic of mash-up culture, an online music scene in which practitioners use audio-editing software to splice and combine pop songs encoded in MP3 format to produce hybrid or “mashed-up” recordings. The study focuses on the logic that guides the development of works, styles and reputations in mash-up culture. Several fields of practice shape this cultural logic, including “virtual studios,” online message boards, dance clubs, and the market for “underground” and “unofficial” remixes. This cultural logic generates a new kind of amateur musicianship based on pluralistic listening and the reorganization of the relations that constitute musical recordings.