Because of recent concerns about the potential dangers of rupture and leakage of silicone-gel implants, radiologists are often requested to evaluate the integrity of normal breast implants. Clinical studies suggest that MR imaging can accurately depict implant rupture. The purpose of this pictorial essay is to illustrate the spectrum of MR appearances of breasts in patients with silicone-gel implants. Types of prostheses range from the more common single-lumen silicone-gel implants to the rare foam-filled implants. Recognition of the variable appearance of intact implants is emphasized in order to distinguish these from intracapsular or extracapsular ruptures. Finally, we briefly review various investigational MR sequences designed to improve the evaluation of the integrity of silicone-gel implants and the localization of free silicone. This article is based on our experience in performing MR imaging in more than 350 patients with breast implants. In more than 50% of these patients, the MR imaging findings have been correlated with surgical and pathologic findings.