This thesis is an investigation into the legitimacy and limits of the term "body art" in its vernacular sense, wherein it refers to methods of decorating or ornamenting the body, such as tattooing or piercing. Though the term is widely used and widely understood, it has rarely appeared in any writing which takes an explicitly arthistorical or art-critical approach, and has never been subjected to any sustained analysis which uses the methodologies deployed by specialists when engaging with other forms of art. If tattooing and its coincident technologies are "body art", they have not as yet been understood as such by art historians. The arguments made over the course of this work thus amount to a case for the applicability of art-historical and art-theoretical methodologies to body modification practice. The thesis first establishes the existence of a rhetorical yet broadly undefended case for the artistic status of practices which alter the form of the body. This claim is to be found amongst both the contemporary subcultural body modification community and amongst plastic surgeons. With particular reference to theories of art and aesthetics by John Dewey, Richard Shusterman, and Gilles Deleuze and Felix Guattari, the work investigates whether such claims are tenable. In light of these investigations, the thesis then presents a number of problems which immediately arise from such a claim - problems of authorship, ownership, objectivity and value - and attempts to resolve them through detailed analysis of a number of case-studies.