Turf wars over medical imaging have become ubiquitous. At many centers, radiologists already have lost access to important technologies and their applications. A combination of decreasing revenues in other specialties and a growing attachment to imaging further threatens radiologists' practices in the future. This is the first of an extended series of articles that will address the phenomenon of self-referral-its motivations, extent, and the threats it poses to radiologists. Each article will focus on a specific aspect and provide advice on how radiologists can deal with self-referral in their locales.